first commit

node_modules/resize-observer-polyfill/LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2016 Denis Rul
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

node_modules/resize-observer-polyfill/README.md

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+ResizeObserver Polyfill
+=============
+
+[![Build Status][travis-image]][travis-url]
+
+
+A polyfill for the Resize Observer API.
+
+Implementation is based on the MutationObserver and uses Mutation Events as a fall back if the first one is not supported, so there will be no polling unless DOM changes. Doesn't modify observed elements. Handles CSS transitions/animations and can possibly observe changes caused by dynamic CSS pseudo-classes, e.g. by `:hover`.
+
+Follows the [spec](http://rawgit.com/WICG/ResizeObserver/master/index.html) and the native implementation. The size is _2.44 KiB_ when minified and gzipped.
+
+[Live demo](http://que-etc.github.io/resize-observer-polyfill) (has style problems in IE10 and lower).
+
+## Installation
+
+From NPM:
+
+```sh
+npm install resize-observer-polyfill --save-dev
+```
+
+~~From Bower:~~ (will be removed with the next major release)
+
+```sh
+bower install resize-observer-polyfill --save-dev
+```
+
+
+## Browser Support
+
+Polyfill has been tested in the following browsers:
+
+[![Build Status](https://saucelabs.com/browser-matrix/que-etc.svg)](https://saucelabs.com/beta/builds/303f5344a7214ba5b62bc7079a15d376)
+
+**NOTE:** Internet Explorer 8 and its earlier versions are not supported.
+
+## Usage Example
+
+It's recommended to use this library in the form of a [ponyfill](https://github.com/sindresorhus/ponyfill), which doesn't inflict modifications of the global object.
+
+```javascript
+import ResizeObserver from 'resize-observer-polyfill';
+
+const ro = new ResizeObserver((entries, observer) => {
+    for (const entry of entries) {
+        const {left, top, width, height} = entry.contentRect;
+
+        console.log('Element:', entry.target);
+        console.log(`Element's size: ${ width }px x ${ height }px`);
+        console.log(`Element's paddings: ${ top }px ; ${ left }px`);
+    }
+});
+
+ro.observe(document.body);
+```
+
+Package's main file is a ES5 [UMD](https://github.com/umdjs/umd) bundle that will be swapped with the ES6 modules version for those bundlers that are aware of the [module](https://github.com/rollup/rollup/wiki/pkg.module) field, e.g. for [Rollup](https://github.com/rollup/rollup) or webpack 2+.
+
+**Note**: global version of the polyfill (`dist/ResizeObserver.global`) is deprecated and will be removed in the next major release.
+
+## Observation Strategy
+
+As mentioned above, this implementation primarily (but not solely) relies on Mutation Observer with a fallback to Mutation Events for IE 9 and IE 10.
+
+Speaking of Mutation Events as a fallback approach: they might not be as ugly as they are being rendered, particularly when their calls are batched, throttled and there is no need to analyze changes. Given that, they won't interrupt browser's reflow/repaint cycles (same for MutationObserver) and may even outperform Internet Explorer's implementation of MO causing little to no performance degradation. In contemporary browsers (Chrome, Firefox, etc.) Mutation Observer slows down [the suite](https://jsfiddle.net/que_etc/gaqLe8rn/) that includes 200 iterations of adding/removing elements, changing attributes and modifying text data by less than 1%. Internet Explorer gives different results with MO slowing down the same suite by 2-3% while Mutation Events show the difference of ~0.6%.
+
+As for the reasons why other approaches, namely the iframe/object and `scroll` strategies, were ruled out:
+* They require the observed element to be non-statically positioned.
+* You can't apply them directly to quite a number of elements: `<img>`, `<input>`, `<textarea>`, `<canvas>`, `<tr>`, `<tbody>`, `<thead>`, `<table>`, etc. For most of them you would need to keep an extra `<div>` wrapper and almost all instances of the SVGGraphicsElement will be out of scope.
+* The ResizeObserver spec requires to deliver notifications when a non-empty visible element becomes hidden, i.e. when either this element directly or one of its parent nodes receive the `display: none` state. Same goes for when it's being removed from or added to the DOM. It's not possible to handle these cases merely by using former approaches, so you'd still need to either subscribe for DOM mutations or to continuously check the element's state.
+
+And though every approach has its own limitations, I reckon that it'd be too much of a trade-off to have those constraints when building a polyfill.
+
+## Limitations
+
+* Notifications are delivered ~20ms after actual changes happen.
+* Changes caused by dynamic pseudo-classes, e.g. `:hover` and `:focus`, are not tracked. As a workaround you could add a short transition which would trigger the `transitionend` event when an element receives one of the former classes ([example](https://jsfiddle.net/que_etc/7fudzqng/)).
+* Delayed transitions will receive only one notification with the latest dimensions of an element.
+
+## Building and Testing
+
+To build polyfill. Creates UMD bundle in the `dist` folder:
+
+```sh
+npm run build
+```
+
+To run a code style test:
+```sh
+npm run test:lint
+```
+
+Running unit tests:
+```sh
+npm run test:spec
+```
+
+To test in a browser that is not present in karma's config file:
+```sh
+npm run test:spec:custom
+```
+
+Testing against a native implementation:
+```sh
+npm run test:spec:native
+```
+
+**NOTE:** after you invoke `spec:native` and `spec:custom` commands head to the `http://localhost:9876/debug.html` page.
+
+[travis-image]: https://travis-ci.org/que-etc/resize-observer-polyfill.svg?branch=master
+[travis-url]: https://travis-ci.org/que-etc/resize-observer-polyfill

node_modules/resize-observer-polyfill/dist/ResizeObserver.es.js

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+/**
+ * A collection of shims that provide minimal functionality of the ES6 collections.
+ *
+ * These implementations are not meant to be used outside of the ResizeObserver
+ * modules as they cover only a limited range of use cases.
+ */
+/* eslint-disable require-jsdoc, valid-jsdoc */
+var MapShim = (function () {
+    if (typeof Map !== 'undefined') {
+        return Map;
+    }
+    /**
+     * Returns index in provided array that matches the specified key.
+     *
+     * @param {Array<Array>} arr
+     * @param {*} key
+     * @returns {number}
+     */
+    function getIndex(arr, key) {
+        var result = -1;
+        arr.some(function (entry, index) {
+            if (entry[0] === key) {
+                result = index;
+                return true;
+            }
+            return false;
+        });
+        return result;
+    }
+    return /** @class */ (function () {
+        function class_1() {
+            this.__entries__ = [];
+        }
+        Object.defineProperty(class_1.prototype, "size", {
+            /**
+             * @returns {boolean}
+             */
+            get: function () {
+                return this.__entries__.length;
+            },
+            enumerable: true,
+            configurable: true
+        });
+        /**
+         * @param {*} key
+         * @returns {*}
+         */
+        class_1.prototype.get = function (key) {
+            var index = getIndex(this.__entries__, key);
+            var entry = this.__entries__[index];
+            return entry && entry[1];
+        };
+        /**
+         * @param {*} key
+         * @param {*} value
+         * @returns {void}
+         */
+        class_1.prototype.set = function (key, value) {
+            var index = getIndex(this.__entries__, key);
+            if (~index) {
+                this.__entries__[index][1] = value;
+            }
+            else {
+                this.__entries__.push([key, value]);
+            }
+        };
+        /**
+         * @param {*} key
+         * @returns {void}
+         */
+        class_1.prototype.delete = function (key) {
+            var entries = this.__entries__;
+            var index = getIndex(entries, key);
+            if (~index) {
+                entries.splice(index, 1);
+            }
+        };
+        /**
+         * @param {*} key
+         * @returns {void}
+         */
+        class_1.prototype.has = function (key) {
+            return !!~getIndex(this.__entries__, key);
+        };
+        /**
+         * @returns {void}
+         */
+        class_1.prototype.clear = function () {
+            this.__entries__.splice(0);
+        };
+        /**
+         * @param {Function} callback
+         * @param {*} [ctx=null]
+         * @returns {void}
+         */
+        class_1.prototype.forEach = function (callback, ctx) {
+            if (ctx === void 0) { ctx = null; }
+            for (var _i = 0, _a = this.__entries__; _i < _a.length; _i++) {
+                var entry = _a[_i];
+                callback.call(ctx, entry[1], entry[0]);
+            }
+        };
+        return class_1;
+    }());
+})();
+
+/**
+ * Detects whether window and document objects are available in current environment.
+ */
+var isBrowser = typeof window !== 'undefined' && typeof document !== 'undefined' && window.document === document;
+
+// Returns global object of a current environment.
+var global$1 = (function () {
+    if (typeof global !== 'undefined' && global.Math === Math) {
+        return global;
+    }
+    if (typeof self !== 'undefined' && self.Math === Math) {
+        return self;
+    }
+    if (typeof window !== 'undefined' && window.Math === Math) {
+        return window;
+    }
+    // eslint-disable-next-line no-new-func
+    return Function('return this')();
+})();
+
+/**
+ * A shim for the requestAnimationFrame which falls back to the setTimeout if
+ * first one is not supported.
+ *
+ * @returns {number} Requests' identifier.
+ */
+var requestAnimationFrame$1 = (function () {
+    if (typeof requestAnimationFrame === 'function') {
+        // It's required to use a bounded function because IE sometimes throws
+        // an "Invalid calling object" error if rAF is invoked without the global
+        // object on the left hand side.
+        return requestAnimationFrame.bind(global$1);
+    }
+    return function (callback) { return setTimeout(function () { return callback(Date.now()); }, 1000 / 60); };
+})();
+
+// Defines minimum timeout before adding a trailing call.
+var trailingTimeout = 2;
+/**
+ * Creates a wrapper function which ensures that provided callback will be
+ * invoked only once during the specified delay period.
+ *
+ * @param {Function} callback - Function to be invoked after the delay period.
+ * @param {number} delay - Delay after which to invoke callback.
+ * @returns {Function}
+ */
+function throttle (callback, delay) {
+    var leadingCall = false, trailingCall = false, lastCallTime = 0;
+    /**
+     * Invokes the original callback function and schedules new invocation if
+     * the "proxy" was called during current request.
+     *
+     * @returns {void}
+     */
+    function resolvePending() {
+        if (leadingCall) {
+            leadingCall = false;
+            callback();
+        }
+        if (trailingCall) {
+            proxy();
+        }
+    }
+    /**
+     * Callback invoked after the specified delay. It will further postpone
+     * invocation of the original function delegating it to the
+     * requestAnimationFrame.
+     *
+     * @returns {void}
+     */
+    function timeoutCallback() {
+        requestAnimationFrame$1(resolvePending);
+    }
+    /**
+     * Schedules invocation of the original function.
+     *
+     * @returns {void}
+     */
+    function proxy() {
+        var timeStamp = Date.now();
+        if (leadingCall) {
+            // Reject immediately following calls.
+            if (timeStamp - lastCallTime < trailingTimeout) {
+                return;
+            }
+            // Schedule new call to be in invoked when the pending one is resolved.
+            // This is important for "transitions" which never actually start
+            // immediately so there is a chance that we might miss one if change
+            // happens amids the pending invocation.
+            trailingCall = true;
+        }
+        else {
+            leadingCall = true;
+            trailingCall = false;
+            setTimeout(timeoutCallback, delay);
+        }
+        lastCallTime = timeStamp;
+    }
+    return proxy;
+}
+
+// Minimum delay before invoking the update of observers.
+var REFRESH_DELAY = 20;
+// A list of substrings of CSS properties used to find transition events that
+// might affect dimensions of observed elements.
+var transitionKeys = ['top', 'right', 'bottom', 'left', 'width', 'height', 'size', 'weight'];
+// Check if MutationObserver is available.
+var mutationObserverSupported = typeof MutationObserver !== 'undefined';
+/**
+ * Singleton controller class which handles updates of ResizeObserver instances.
+ */
+var ResizeObserverController = /** @class */ (function () {
+    /**
+     * Creates a new instance of ResizeObserverController.
+     *
+     * @private
+     */
+    function ResizeObserverController() {
+        /**
+         * Indicates whether DOM listeners have been added.
+         *
+         * @private {boolean}
+         */
+        this.connected_ = false;
+        /**
+         * Tells that controller has subscribed for Mutation Events.
+         *
+         * @private {boolean}
+         */
+        this.mutationEventsAdded_ = false;
+        /**
+         * Keeps reference to the instance of MutationObserver.
+         *
+         * @private {MutationObserver}
+         */
+        this.mutationsObserver_ = null;
+        /**
+         * A list of connected observers.
+         *
+         * @private {Array<ResizeObserverSPI>}
+         */
+        this.observers_ = [];
+        this.onTransitionEnd_ = this.onTransitionEnd_.bind(this);
+        this.refresh = throttle(this.refresh.bind(this), REFRESH_DELAY);
+    }
+    /**
+     * Adds observer to observers list.
+     *
+     * @param {ResizeObserverSPI} observer - Observer to be added.
+     * @returns {void}
+     */
+    ResizeObserverController.prototype.addObserver = function (observer) {
+        if (!~this.observers_.indexOf(observer)) {
+            this.observers_.push(observer);
+        }
+        // Add listeners if they haven't been added yet.
+        if (!this.connected_) {
+            this.connect_();
+        }
+    };
+    /**
+     * Removes observer from observers list.
+     *
+     * @param {ResizeObserverSPI} observer - Observer to be removed.
+     * @returns {void}
+     */
+    ResizeObserverController.prototype.removeObserver = function (observer) {
+        var observers = this.observers_;
+        var index = observers.indexOf(observer);
+        // Remove observer if it's present in registry.
+        if (~index) {
+            observers.splice(index, 1);
+        }
+        // Remove listeners if controller has no connected observers.
+        if (!observers.length && this.connected_) {
+            this.disconnect_();
+        }
+    };
+    /**
+     * Invokes the update of observers. It will continue running updates insofar
+     * it detects changes.
+     *
+     * @returns {void}
+     */
+    ResizeObserverController.prototype.refresh = function () {
+        var changesDetected = this.updateObservers_();
+        // Continue running updates if changes have been detected as there might
+        // be future ones caused by CSS transitions.
+        if (changesDetected) {
+            this.refresh();
+        }
+    };
+    /**
+     * Updates every observer from observers list and notifies them of queued
+     * entries.
+     *
+     * @private
+     * @returns {boolean} Returns "true" if any observer has detected changes in
+     *      dimensions of it's elements.
+     */
+    ResizeObserverController.prototype.updateObservers_ = function () {
+        // Collect observers that have active observations.
+        var activeObservers = this.observers_.filter(function (observer) {
+            return observer.gatherActive(), observer.hasActive();
+        });
+        // Deliver notifications in a separate cycle in order to avoid any
+        // collisions between observers, e.g. when multiple instances of
+        // ResizeObserver are tracking the same element and the callback of one
+        // of them changes content dimensions of the observed target. Sometimes
+        // this may result in notifications being blocked for the rest of observers.
+        activeObservers.forEach(function (observer) { return observer.broadcastActive(); });
+        return activeObservers.length > 0;
+    };
+    /**
+     * Initializes DOM listeners.
+     *
+     * @private
+     * @returns {void}
+     */
+    ResizeObserverController.prototype.connect_ = function () {
+        // Do nothing if running in a non-browser environment or if listeners
+        // have been already added.
+        if (!isBrowser || this.connected_) {
+            return;
+        }
+        // Subscription to the "Transitionend" event is used as a workaround for
+        // delayed transitions. This way it's possible to capture at least the
+        // final state of an element.
+        document.addEventListener('transitionend', this.onTransitionEnd_);
+        window.addEventListener('resize', this.refresh);
+        if (mutationObserverSupported) {
+            this.mutationsObserver_ = new MutationObserver(this.refresh);
+            this.mutationsObserver_.observe(document, {
+                attributes: true,
+                childList: true,
+                characterData: true,
+                subtree: true
+            });
+        }
+        else {
+            document.addEventListener('DOMSubtreeModified', this.refresh);
+            this.mutationEventsAdded_ = true;
+        }
+        this.connected_ = true;
+    };
+    /**
+     * Removes DOM listeners.
+     *
+     * @private
+     * @returns {void}
+     */
+    ResizeObserverController.prototype.disconnect_ = function () {
+        // Do nothing if running in a non-browser environment or if listeners
+        // have been already removed.
+        if (!isBrowser || !this.connected_) {
+            return;
+        }
+        document.removeEventListener('transitionend', this.onTransitionEnd_);
+        window.removeEventListener('resize', this.refresh);
+        if (this.mutationsObserver_) {
+            this.mutationsObserver_.disconnect();
+        }
+        if (this.mutationEventsAdded_) {
+            document.removeEventListener('DOMSubtreeModified', this.refresh);
+        }
+        this.mutationsObserver_ = null;
+        this.mutationEventsAdded_ = false;
+        this.connected_ = false;
+    };
+    /**
+     * "Transitionend" event handler.
+     *
+     * @private
+     * @param {TransitionEvent} event
+     * @returns {void}
+     */
+    ResizeObserverController.prototype.onTransitionEnd_ = function (_a) {
+        var _b = _a.propertyName, propertyName = _b === void 0 ? '' : _b;
+        // Detect whether transition may affect dimensions of an element.
+        var isReflowProperty = transitionKeys.some(function (key) {
+            return !!~propertyName.indexOf(key);
+        });
+        if (isReflowProperty) {
+            this.refresh();
+        }
+    };
+    /**
+     * Returns instance of the ResizeObserverController.
+     *
+     * @returns {ResizeObserverController}
+     */
+    ResizeObserverController.getInstance = function () {
+        if (!this.instance_) {
+            this.instance_ = new ResizeObserverController();
+        }
+        return this.instance_;
+    };
+    /**
+     * Holds reference to the controller's instance.
+     *
+     * @private {ResizeObserverController}
+     */
+    ResizeObserverController.instance_ = null;
+    return ResizeObserverController;
+}());
+
+/**
+ * Defines non-writable/enumerable properties of the provided target object.
+ *
+ * @param {Object} target - Object for which to define properties.
+ * @param {Object} props - Properties to be defined.
+ * @returns {Object} Target object.
+ */
+var defineConfigurable = (function (target, props) {
+    for (var _i = 0, _a = Object.keys(props); _i < _a.length; _i++) {
+        var key = _a[_i];
+        Object.defineProperty(target, key, {
+            value: props[key],
+            enumerable: false,
+            writable: false,
+            configurable: true
+        });
+    }
+    return target;
+});
+
+/**
+ * Returns the global object associated with provided element.
+ *
+ * @param {Object} target
+ * @returns {Object}
+ */
+var getWindowOf = (function (target) {
+    // Assume that the element is an instance of Node, which means that it
+    // has the "ownerDocument" property from which we can retrieve a
+    // corresponding global object.
+    var ownerGlobal = target && target.ownerDocument && target.ownerDocument.defaultView;
+    // Return the local global object if it's not possible extract one from
+    // provided element.
+    return ownerGlobal || global$1;
+});
+
+// Placeholder of an empty content rectangle.
+var emptyRect = createRectInit(0, 0, 0, 0);
+/**
+ * Converts provided string to a number.
+ *
+ * @param {number|string} value
+ * @returns {number}
+ */
+function toFloat(value) {
+    return parseFloat(value) || 0;
+}
+/**
+ * Extracts borders size from provided styles.
+ *
+ * @param {CSSStyleDeclaration} styles
+ * @param {...string} positions - Borders positions (top, right, ...)
+ * @returns {number}
+ */
+function getBordersSize(styles) {
+    var positions = [];
+    for (var _i = 1; _i < arguments.length; _i++) {
+        positions[_i - 1] = arguments[_i];
+    }
+    return positions.reduce(function (size, position) {
+        var value = styles['border-' + position + '-width'];
+        return size + toFloat(value);
+    }, 0);
+}
+/**
+ * Extracts paddings sizes from provided styles.
+ *
+ * @param {CSSStyleDeclaration} styles
+ * @returns {Object} Paddings box.
+ */
+function getPaddings(styles) {
+    var positions = ['top', 'right', 'bottom', 'left'];
+    var paddings = {};
+    for (var _i = 0, positions_1 = positions; _i < positions_1.length; _i++) {
+        var position = positions_1[_i];
+        var value = styles['padding-' + position];
+        paddings[position] = toFloat(value);
+    }
+    return paddings;
+}
+/**
+ * Calculates content rectangle of provided SVG element.
+ *
+ * @param {SVGGraphicsElement} target - Element content rectangle of which needs
+ *      to be calculated.
+ * @returns {DOMRectInit}
+ */
+function getSVGContentRect(target) {
+    var bbox = target.getBBox();
+    return createRectInit(0, 0, bbox.width, bbox.height);
+}
+/**
+ * Calculates content rectangle of provided HTMLElement.
+ *
+ * @param {HTMLElement} target - Element for which to calculate the content rectangle.
+ * @returns {DOMRectInit}
+ */
+function getHTMLElementContentRect(target) {
+    // Client width & height properties can't be
+    // used exclusively as they provide rounded values.
+    var clientWidth = target.clientWidth, clientHeight = target.clientHeight;
+    // By this condition we can catch all non-replaced inline, hidden and
+    // detached elements. Though elements with width & height properties less
+    // than 0.5 will be discarded as well.
+    //
+    // Without it we would need to implement separate methods for each of
+    // those cases and it's not possible to perform a precise and performance
+    // effective test for hidden elements. E.g. even jQuery's ':visible' filter
+    // gives wrong results for elements with width & height less than 0.5.
+    if (!clientWidth && !clientHeight) {
+        return emptyRect;
+    }
+    var styles = getWindowOf(target).getComputedStyle(target);
+    var paddings = getPaddings(styles);
+    var horizPad = paddings.left + paddings.right;
+    var vertPad = paddings.top + paddings.bottom;
+    // Computed styles of width & height are being used because they are the
+    // only dimensions available to JS that contain non-rounded values. It could
+    // be possible to utilize the getBoundingClientRect if only it's data wasn't
+    // affected by CSS transformations let alone paddings, borders and scroll bars.
+    var width = toFloat(styles.width), height = toFloat(styles.height);
+    // Width & height include paddings and borders when the 'border-box' box
+    // model is applied (except for IE).
+    if (styles.boxSizing === 'border-box') {
+        // Following conditions are required to handle Internet Explorer which
+        // doesn't include paddings and borders to computed CSS dimensions.
+        //
+        // We can say that if CSS dimensions + paddings are equal to the "client"
+        // properties then it's either IE, and thus we don't need to subtract
+        // anything, or an element merely doesn't have paddings/borders styles.
+        if (Math.round(width + horizPad) !== clientWidth) {
+            width -= getBordersSize(styles, 'left', 'right') + horizPad;
+        }
+        if (Math.round(height + vertPad) !== clientHeight) {
+            height -= getBordersSize(styles, 'top', 'bottom') + vertPad;
+        }
+    }
+    // Following steps can't be applied to the document's root element as its
+    // client[Width/Height] properties represent viewport area of the window.
+    // Besides, it's as well not necessary as the <html> itself neither has
+    // rendered scroll bars nor it can be clipped.
+    if (!isDocumentElement(target)) {
+        // In some browsers (only in Firefox, actually) CSS width & height
+        // include scroll bars size which can be removed at this step as scroll
+        // bars are the only difference between rounded dimensions + paddings
+        // and "client" properties, though that is not always true in Chrome.
+        var vertScrollbar = Math.round(width + horizPad) - clientWidth;
+        var horizScrollbar = Math.round(height + vertPad) - clientHeight;
+        // Chrome has a rather weird rounding of "client" properties.
+        // E.g. for an element with content width of 314.2px it sometimes gives
+        // the client width of 315px and for the width of 314.7px it may give
+        // 314px. And it doesn't happen all the time. So just ignore this delta
+        // as a non-relevant.
+        if (Math.abs(vertScrollbar) !== 1) {
+            width -= vertScrollbar;
+        }
+        if (Math.abs(horizScrollbar) !== 1) {
+            height -= horizScrollbar;
+        }
+    }
+    return createRectInit(paddings.left, paddings.top, width, height);
+}
+/**
+ * Checks whether provided element is an instance of the SVGGraphicsElement.
+ *
+ * @param {Element} target - Element to be checked.
+ * @returns {boolean}
+ */
+var isSVGGraphicsElement = (function () {
+    // Some browsers, namely IE and Edge, don't have the SVGGraphicsElement
+    // interface.
+    if (typeof SVGGraphicsElement !== 'undefined') {
+        return function (target) { return target instanceof getWindowOf(target).SVGGraphicsElement; };
+    }
+    // If it's so, then check that element is at least an instance of the
+    // SVGElement and that it has the "getBBox" method.
+    // eslint-disable-next-line no-extra-parens
+    return function (target) { return (target instanceof getWindowOf(target).SVGElement &&
+        typeof target.getBBox === 'function'); };
+})();
+/**
+ * Checks whether provided element is a document element (<html>).
+ *
+ * @param {Element} target - Element to be checked.
+ * @returns {boolean}
+ */
+function isDocumentElement(target) {
+    return target === getWindowOf(target).document.documentElement;
+}
+/**
+ * Calculates an appropriate content rectangle for provided html or svg element.
+ *
+ * @param {Element} target - Element content rectangle of which needs to be calculated.
+ * @returns {DOMRectInit}
+ */
+function getContentRect(target) {
+    if (!isBrowser) {
+        return emptyRect;
+    }
+    if (isSVGGraphicsElement(target)) {
+        return getSVGContentRect(target);
+    }
+    return getHTMLElementContentRect(target);
+}
+/**
+ * Creates rectangle with an interface of the DOMRectReadOnly.
+ * Spec: https://drafts.fxtf.org/geometry/#domrectreadonly
+ *
+ * @param {DOMRectInit} rectInit - Object with rectangle's x/y coordinates and dimensions.
+ * @returns {DOMRectReadOnly}
+ */
+function createReadOnlyRect(_a) {
+    var x = _a.x, y = _a.y, width = _a.width, height = _a.height;
+    // If DOMRectReadOnly is available use it as a prototype for the rectangle.
+    var Constr = typeof DOMRectReadOnly !== 'undefined' ? DOMRectReadOnly : Object;
+    var rect = Object.create(Constr.prototype);
+    // Rectangle's properties are not writable and non-enumerable.
+    defineConfigurable(rect, {
+        x: x, y: y, width: width, height: height,
+        top: y,
+        right: x + width,
+        bottom: height + y,
+        left: x
+    });
+    return rect;
+}
+/**
+ * Creates DOMRectInit object based on the provided dimensions and the x/y coordinates.
+ * Spec: https://drafts.fxtf.org/geometry/#dictdef-domrectinit
+ *
+ * @param {number} x - X coordinate.
+ * @param {number} y - Y coordinate.
+ * @param {number} width - Rectangle's width.
+ * @param {number} height - Rectangle's height.
+ * @returns {DOMRectInit}
+ */
+function createRectInit(x, y, width, height) {
+    return { x: x, y: y, width: width, height: height };
+}
+
+/**
+ * Class that is responsible for computations of the content rectangle of
+ * provided DOM element and for keeping track of it's changes.
+ */
+var ResizeObservation = /** @class */ (function () {
+    /**
+     * Creates an instance of ResizeObservation.
+     *
+     * @param {Element} target - Element to be observed.
+     */
+    function ResizeObservation(target) {
+        /**
+         * Broadcasted width of content rectangle.
+         *
+         * @type {number}
+         */
+        this.broadcastWidth = 0;
+        /**
+         * Broadcasted height of content rectangle.
+         *
+         * @type {number}
+         */
+        this.broadcastHeight = 0;
+        /**
+         * Reference to the last observed content rectangle.
+         *
+         * @private {DOMRectInit}
+         */
+        this.contentRect_ = createRectInit(0, 0, 0, 0);
+        this.target = target;
+    }
+    /**
+     * Updates content rectangle and tells whether it's width or height properties
+     * have changed since the last broadcast.
+     *
+     * @returns {boolean}
+     */
+    ResizeObservation.prototype.isActive = function () {
+        var rect = getContentRect(this.target);
+        this.contentRect_ = rect;
+        return (rect.width !== this.broadcastWidth ||
+            rect.height !== this.broadcastHeight);
+    };
+    /**
+     * Updates 'broadcastWidth' and 'broadcastHeight' properties with a data
+     * from the corresponding properties of the last observed content rectangle.
+     *
+     * @returns {DOMRectInit} Last observed content rectangle.
+     */
+    ResizeObservation.prototype.broadcastRect = function () {
+        var rect = this.contentRect_;
+        this.broadcastWidth = rect.width;
+        this.broadcastHeight = rect.height;
+        return rect;
+    };
+    return ResizeObservation;
+}());
+
+var ResizeObserverEntry = /** @class */ (function () {
+    /**
+     * Creates an instance of ResizeObserverEntry.
+     *
+     * @param {Element} target - Element that is being observed.
+     * @param {DOMRectInit} rectInit - Data of the element's content rectangle.
+     */
+    function ResizeObserverEntry(target, rectInit) {
+        var contentRect = createReadOnlyRect(rectInit);
+        // According to the specification following properties are not writable
+        // and are also not enumerable in the native implementation.
+        //
+        // Property accessors are not being used as they'd require to define a
+        // private WeakMap storage which may cause memory leaks in browsers that
+        // don't support this type of collections.
+        defineConfigurable(this, { target: target, contentRect: contentRect });
+    }
+    return ResizeObserverEntry;
+}());
+
+var ResizeObserverSPI = /** @class */ (function () {
+    /**
+     * Creates a new instance of ResizeObserver.
+     *
+     * @param {ResizeObserverCallback} callback - Callback function that is invoked
+     *      when one of the observed elements changes it's content dimensions.
+     * @param {ResizeObserverController} controller - Controller instance which
+     *      is responsible for the updates of observer.
+     * @param {ResizeObserver} callbackCtx - Reference to the public
+     *      ResizeObserver instance which will be passed to callback function.
+     */
+    function ResizeObserverSPI(callback, controller, callbackCtx) {
+        /**
+         * Collection of resize observations that have detected changes in dimensions
+         * of elements.
+         *
+         * @private {Array<ResizeObservation>}
+         */
+        this.activeObservations_ = [];
+        /**
+         * Registry of the ResizeObservation instances.
+         *
+         * @private {Map<Element, ResizeObservation>}
+         */
+        this.observations_ = new MapShim();
+        if (typeof callback !== 'function') {
+            throw new TypeError('The callback provided as parameter 1 is not a function.');
+        }
+        this.callback_ = callback;
+        this.controller_ = controller;
+        this.callbackCtx_ = callbackCtx;
+    }
+    /**
+     * Starts observing provided element.
+     *
+     * @param {Element} target - Element to be observed.
+     * @returns {void}
+     */
+    ResizeObserverSPI.prototype.observe = function (target) {
+        if (!arguments.length) {
+            throw new TypeError('1 argument required, but only 0 present.');
+        }
+        // Do nothing if current environment doesn't have the Element interface.
+        if (typeof Element === 'undefined' || !(Element instanceof Object)) {
+            return;
+        }
+        if (!(target instanceof getWindowOf(target).Element)) {
+            throw new TypeError('parameter 1 is not of type "Element".');
+        }
+        var observations = this.observations_;
+        // Do nothing if element is already being observed.
+        if (observations.has(target)) {
+            return;
+        }
+        observations.set(target, new ResizeObservation(target));
+        this.controller_.addObserver(this);
+        // Force the update of observations.
+        this.controller_.refresh();
+    };
+    /**
+     * Stops observing provided element.
+     *
+     * @param {Element} target - Element to stop observing.
+     * @returns {void}
+     */
+    ResizeObserverSPI.prototype.unobserve = function (target) {
+        if (!arguments.length) {
+            throw new TypeError('1 argument required, but only 0 present.');
+        }
+        // Do nothing if current environment doesn't have the Element interface.
+        if (typeof Element === 'undefined' || !(Element instanceof Object)) {
+            return;
+        }
+        if (!(target instanceof getWindowOf(target).Element)) {
+            throw new TypeError('parameter 1 is not of type "Element".');
+        }
+        var observations = this.observations_;
+        // Do nothing if element is not being observed.
+        if (!observations.has(target)) {
+            return;
+        }
+        observations.delete(target);
+        if (!observations.size) {
+            this.controller_.removeObserver(this);
+        }
+    };
+    /**
+     * Stops observing all elements.
+     *
+     * @returns {void}
+     */
+    ResizeObserverSPI.prototype.disconnect = function () {
+        this.clearActive();
+        this.observations_.clear();
+        this.controller_.removeObserver(this);
+    };
+    /**
+     * Collects observation instances the associated element of which has changed
+     * it's content rectangle.
+     *
+     * @returns {void}
+     */
+    ResizeObserverSPI.prototype.gatherActive = function () {
+        var _this = this;
+        this.clearActive();
+        this.observations_.forEach(function (observation) {
+            if (observation.isActive()) {
+                _this.activeObservations_.push(observation);
+            }
+        });
+    };
+    /**
+     * Invokes initial callback function with a list of ResizeObserverEntry
+     * instances collected from active resize observations.
+     *
+     * @returns {void}
+     */
+    ResizeObserverSPI.prototype.broadcastActive = function () {
+        // Do nothing if observer doesn't have active observations.
+        if (!this.hasActive()) {
+            return;
+        }
+        var ctx = this.callbackCtx_;
+        // Create ResizeObserverEntry instance for every active observation.
+        var entries = this.activeObservations_.map(function (observation) {
+            return new ResizeObserverEntry(observation.target, observation.broadcastRect());
+        });
+        this.callback_.call(ctx, entries, ctx);
+        this.clearActive();
+    };
+    /**
+     * Clears the collection of active observations.
+     *
+     * @returns {void}
+     */
+    ResizeObserverSPI.prototype.clearActive = function () {
+        this.activeObservations_.splice(0);
+    };
+    /**
+     * Tells whether observer has active observations.
+     *
+     * @returns {boolean}
+     */
+    ResizeObserverSPI.prototype.hasActive = function () {
+        return this.activeObservations_.length > 0;
+    };
+    return ResizeObserverSPI;
+}());
+
+// Registry of internal observers. If WeakMap is not available use current shim
+// for the Map collection as it has all required methods and because WeakMap
+// can't be fully polyfilled anyway.
+var observers = typeof WeakMap !== 'undefined' ? new WeakMap() : new MapShim();
+/**
+ * ResizeObserver API. Encapsulates the ResizeObserver SPI implementation
+ * exposing only those methods and properties that are defined in the spec.
+ */
+var ResizeObserver = /** @class */ (function () {
+    /**
+     * Creates a new instance of ResizeObserver.
+     *
+     * @param {ResizeObserverCallback} callback - Callback that is invoked when
+     *      dimensions of the observed elements change.
+     */
+    function ResizeObserver(callback) {
+        if (!(this instanceof ResizeObserver)) {
+            throw new TypeError('Cannot call a class as a function.');
+        }
+        if (!arguments.length) {
+            throw new TypeError('1 argument required, but only 0 present.');
+        }
+        var controller = ResizeObserverController.getInstance();
+        var observer = new ResizeObserverSPI(callback, controller, this);
+        observers.set(this, observer);
+    }
+    return ResizeObserver;
+}());
+// Expose public methods of ResizeObserver.
+[
+    'observe',
+    'unobserve',
+    'disconnect'
+].forEach(function (method) {
+    ResizeObserver.prototype[method] = function () {
+        var _a;
+        return (_a = observers.get(this))[method].apply(_a, arguments);
+    };
+});
+
+var index = (function () {
+    // Export existing implementation if available.
+    if (typeof global$1.ResizeObserver !== 'undefined') {
+        return global$1.ResizeObserver;
+    }
+    return ResizeObserver;
+})();
+
+export default index;

node_modules/resize-observer-polyfill/dist/ResizeObserver.js

@@ -0,0 +1,936 @@
+(function (global, factory) {
+    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
+    typeof define === 'function' && define.amd ? define(factory) :
+    (global.ResizeObserver = factory());
+}(this, (function () { 'use strict';
+
+    /**
+     * A collection of shims that provide minimal functionality of the ES6 collections.
+     *
+     * These implementations are not meant to be used outside of the ResizeObserver
+     * modules as they cover only a limited range of use cases.
+     */
+    /* eslint-disable require-jsdoc, valid-jsdoc */
+    var MapShim = (function () {
+        if (typeof Map !== 'undefined') {
+            return Map;
+        }
+        /**
+         * Returns index in provided array that matches the specified key.
+         *
+         * @param {Array<Array>} arr
+         * @param {*} key
+         * @returns {number}
+         */
+        function getIndex(arr, key) {
+            var result = -1;
+            arr.some(function (entry, index) {
+                if (entry[0] === key) {
+                    result = index;
+                    return true;
+                }
+                return false;
+            });
+            return result;
+        }
+        return /** @class */ (function () {
+            function class_1() {
+                this.__entries__ = [];
+            }
+            Object.defineProperty(class_1.prototype, "size", {
+                /**
+                 * @returns {boolean}
+                 */
+                get: function () {
+                    return this.__entries__.length;
+                },
+                enumerable: true,
+                configurable: true
+            });
+            /**
+             * @param {*} key
+             * @returns {*}
+             */
+            class_1.prototype.get = function (key) {
+                var index = getIndex(this.__entries__, key);
+                var entry = this.__entries__[index];
+                return entry && entry[1];
+            };
+            /**
+             * @param {*} key
+             * @param {*} value
+             * @returns {void}
+             */
+            class_1.prototype.set = function (key, value) {
+                var index = getIndex(this.__entries__, key);
+                if (~index) {
+                    this.__entries__[index][1] = value;
+                }
+                else {
+                    this.__entries__.push([key, value]);
+                }
+            };
+            /**
+             * @param {*} key
+             * @returns {void}
+             */
+            class_1.prototype.delete = function (key) {
+                var entries = this.__entries__;
+                var index = getIndex(entries, key);
+                if (~index) {
+                    entries.splice(index, 1);
+                }
+            };
+            /**
+             * @param {*} key
+             * @returns {void}
+             */
+            class_1.prototype.has = function (key) {
+                return !!~getIndex(this.__entries__, key);
+            };
+            /**
+             * @returns {void}
+             */
+            class_1.prototype.clear = function () {
+                this.__entries__.splice(0);
+            };
+            /**
+             * @param {Function} callback
+             * @param {*} [ctx=null]
+             * @returns {void}
+             */
+            class_1.prototype.forEach = function (callback, ctx) {
+                if (ctx === void 0) { ctx = null; }
+                for (var _i = 0, _a = this.__entries__; _i < _a.length; _i++) {
+                    var entry = _a[_i];
+                    callback.call(ctx, entry[1], entry[0]);
+                }
+            };
+            return class_1;
+        }());
+    })();
+
+    /**
+     * Detects whether window and document objects are available in current environment.
+     */
+    var isBrowser = typeof window !== 'undefined' && typeof document !== 'undefined' && window.document === document;
+
+    // Returns global object of a current environment.
+    var global$1 = (function () {
+        if (typeof global !== 'undefined' && global.Math === Math) {
+            return global;
+        }
+        if (typeof self !== 'undefined' && self.Math === Math) {
+            return self;
+        }
+        if (typeof window !== 'undefined' && window.Math === Math) {
+            return window;
+        }
+        // eslint-disable-next-line no-new-func
+        return Function('return this')();
+    })();
+
+    /**
+     * A shim for the requestAnimationFrame which falls back to the setTimeout if
+     * first one is not supported.
+     *
+     * @returns {number} Requests' identifier.
+     */
+    var requestAnimationFrame$1 = (function () {
+        if (typeof requestAnimationFrame === 'function') {
+            // It's required to use a bounded function because IE sometimes throws
+            // an "Invalid calling object" error if rAF is invoked without the global
+            // object on the left hand side.
+            return requestAnimationFrame.bind(global$1);
+        }
+        return function (callback) { return setTimeout(function () { return callback(Date.now()); }, 1000 / 60); };
+    })();
+
+    // Defines minimum timeout before adding a trailing call.
+    var trailingTimeout = 2;
+    /**
+     * Creates a wrapper function which ensures that provided callback will be
+     * invoked only once during the specified delay period.
+     *
+     * @param {Function} callback - Function to be invoked after the delay period.
+     * @param {number} delay - Delay after which to invoke callback.
+     * @returns {Function}
+     */
+    function throttle (callback, delay) {
+        var leadingCall = false, trailingCall = false, lastCallTime = 0;
+        /**
+         * Invokes the original callback function and schedules new invocation if
+         * the "proxy" was called during current request.
+         *
+         * @returns {void}
+         */
+        function resolvePending() {
+            if (leadingCall) {
+                leadingCall = false;
+                callback();
+            }
+            if (trailingCall) {
+                proxy();
+            }
+        }
+        /**
+         * Callback invoked after the specified delay. It will further postpone
+         * invocation of the original function delegating it to the
+         * requestAnimationFrame.
+         *
+         * @returns {void}
+         */
+        function timeoutCallback() {
+            requestAnimationFrame$1(resolvePending);
+        }
+        /**
+         * Schedules invocation of the original function.
+         *
+         * @returns {void}
+         */
+        function proxy() {
+            var timeStamp = Date.now();
+            if (leadingCall) {
+                // Reject immediately following calls.
+                if (timeStamp - lastCallTime < trailingTimeout) {
+                    return;
+                }
+                // Schedule new call to be in invoked when the pending one is resolved.
+                // This is important for "transitions" which never actually start
+                // immediately so there is a chance that we might miss one if change
+                // happens amids the pending invocation.
+                trailingCall = true;
+            }
+            else {
+                leadingCall = true;
+                trailingCall = false;
+                setTimeout(timeoutCallback, delay);
+            }
+            lastCallTime = timeStamp;
+        }
+        return proxy;
+    }
+
+    // Minimum delay before invoking the update of observers.
+    var REFRESH_DELAY = 20;
+    // A list of substrings of CSS properties used to find transition events that
+    // might affect dimensions of observed elements.
+    var transitionKeys = ['top', 'right', 'bottom', 'left', 'width', 'height', 'size', 'weight'];
+    // Check if MutationObserver is available.
+    var mutationObserverSupported = typeof MutationObserver !== 'undefined';
+    /**
+     * Singleton controller class which handles updates of ResizeObserver instances.
+     */
+    var ResizeObserverController = /** @class */ (function () {
+        /**
+         * Creates a new instance of ResizeObserverController.
+         *
+         * @private
+         */
+        function ResizeObserverController() {
+            /**
+             * Indicates whether DOM listeners have been added.
+             *
+             * @private {boolean}
+             */
+            this.connected_ = false;
+            /**
+             * Tells that controller has subscribed for Mutation Events.
+             *
+             * @private {boolean}
+             */
+            this.mutationEventsAdded_ = false;
+            /**
+             * Keeps reference to the instance of MutationObserver.
+             *
+             * @private {MutationObserver}
+             */
+            this.mutationsObserver_ = null;
+            /**
+             * A list of connected observers.
+             *
+             * @private {Array<ResizeObserverSPI>}
+             */
+            this.observers_ = [];
+            this.onTransitionEnd_ = this.onTransitionEnd_.bind(this);
+            this.refresh = throttle(this.refresh.bind(this), REFRESH_DELAY);
+        }
+        /**
+         * Adds observer to observers list.
+         *
+         * @param {ResizeObserverSPI} observer - Observer to be added.
+         * @returns {void}
+         */
+        ResizeObserverController.prototype.addObserver = function (observer) {
+            if (!~this.observers_.indexOf(observer)) {
+                this.observers_.push(observer);
+            }
+            // Add listeners if they haven't been added yet.
+            if (!this.connected_) {
+                this.connect_();
+            }
+        };
+        /**
+         * Removes observer from observers list.
+         *
+         * @param {ResizeObserverSPI} observer - Observer to be removed.
+         * @returns {void}
+         */
+        ResizeObserverController.prototype.removeObserver = function (observer) {
+            var observers = this.observers_;
+            var index = observers.indexOf(observer);
+            // Remove observer if it's present in registry.
+            if (~index) {
+                observers.splice(index, 1);
+            }
+            // Remove listeners if controller has no connected observers.
+            if (!observers.length && this.connected_) {
+                this.disconnect_();
+            }
+        };
+        /**
+         * Invokes the update of observers. It will continue running updates insofar
+         * it detects changes.
+         *
+         * @returns {void}
+         */
+        ResizeObserverController.prototype.refresh = function () {
+            var changesDetected = this.updateObservers_();
+            // Continue running updates if changes have been detected as there might
+            // be future ones caused by CSS transitions.
+            if (changesDetected) {
+                this.refresh();
+            }
+        };
+        /**
+         * Updates every observer from observers list and notifies them of queued
+         * entries.
+         *
+         * @private
+         * @returns {boolean} Returns "true" if any observer has detected changes in
+         *      dimensions of it's elements.
+         */
+        ResizeObserverController.prototype.updateObservers_ = function () {
+            // Collect observers that have active observations.
+            var activeObservers = this.observers_.filter(function (observer) {
+                return observer.gatherActive(), observer.hasActive();
+            });
+            // Deliver notifications in a separate cycle in order to avoid any
+            // collisions between observers, e.g. when multiple instances of
+            // ResizeObserver are tracking the same element and the callback of one
+            // of them changes content dimensions of the observed target. Sometimes
+            // this may result in notifications being blocked for the rest of observers.
+            activeObservers.forEach(function (observer) { return observer.broadcastActive(); });
+            return activeObservers.length > 0;
+        };
+        /**
+         * Initializes DOM listeners.
+         *
+         * @private
+         * @returns {void}
+         */
+        ResizeObserverController.prototype.connect_ = function () {
+            // Do nothing if running in a non-browser environment or if listeners
+            // have been already added.
+            if (!isBrowser || this.connected_) {
+                return;
+            }
+            // Subscription to the "Transitionend" event is used as a workaround for
+            // delayed transitions. This way it's possible to capture at least the
+            // final state of an element.
+            document.addEventListener('transitionend', this.onTransitionEnd_);
+            window.addEventListener('resize', this.refresh);
+            if (mutationObserverSupported) {
+                this.mutationsObserver_ = new MutationObserver(this.refresh);
+                this.mutationsObserver_.observe(document, {
+                    attributes: true,
+                    childList: true,
+                    characterData: true,
+                    subtree: true
+                });
+            }
+            else {
+                document.addEventListener('DOMSubtreeModified', this.refresh);
+                this.mutationEventsAdded_ = true;
+            }
+            this.connected_ = true;
+        };
+        /**
+         * Removes DOM listeners.
+         *
+         * @private
+         * @returns {void}
+         */
+        ResizeObserverController.prototype.disconnect_ = function () {
+            // Do nothing if running in a non-browser environment or if listeners
+            // have been already removed.
+            if (!isBrowser || !this.connected_) {
+                return;
+            }
+            document.removeEventListener('transitionend', this.onTransitionEnd_);
+            window.removeEventListener('resize', this.refresh);
+            if (this.mutationsObserver_) {
+                this.mutationsObserver_.disconnect();
+            }
+            if (this.mutationEventsAdded_) {
+                document.removeEventListener('DOMSubtreeModified', this.refresh);
+            }
+            this.mutationsObserver_ = null;
+            this.mutationEventsAdded_ = false;
+            this.connected_ = false;
+        };
+        /**
+         * "Transitionend" event handler.
+         *
+         * @private
+         * @param {TransitionEvent} event
+         * @returns {void}
+         */
+        ResizeObserverController.prototype.onTransitionEnd_ = function (_a) {
+            var _b = _a.propertyName, propertyName = _b === void 0 ? '' : _b;
+            // Detect whether transition may affect dimensions of an element.
+            var isReflowProperty = transitionKeys.some(function (key) {
+                return !!~propertyName.indexOf(key);
+            });
+            if (isReflowProperty) {
+                this.refresh();
+            }
+        };
+        /**
+         * Returns instance of the ResizeObserverController.
+         *
+         * @returns {ResizeObserverController}
+         */
+        ResizeObserverController.getInstance = function () {
+            if (!this.instance_) {
+                this.instance_ = new ResizeObserverController();
+            }
+            return this.instance_;
+        };
+        /**
+         * Holds reference to the controller's instance.
+         *
+         * @private {ResizeObserverController}
+         */
+        ResizeObserverController.instance_ = null;
+        return ResizeObserverController;
+    }());
+
+    /**
+     * Defines non-writable/enumerable properties of the provided target object.
+     *
+     * @param {Object} target - Object for which to define properties.
+     * @param {Object} props - Properties to be defined.
+     * @returns {Object} Target object.
+     */
+    var defineConfigurable = (function (target, props) {
+        for (var _i = 0, _a = Object.keys(props); _i < _a.length; _i++) {
+            var key = _a[_i];
+            Object.defineProperty(target, key, {
+                value: props[key],
+                enumerable: false,
+                writable: false,
+                configurable: true
+            });
+        }
+        return target;
+    });
+
+    /**
+     * Returns the global object associated with provided element.
+     *
+     * @param {Object} target
+     * @returns {Object}
+     */
+    var getWindowOf = (function (target) {
+        // Assume that the element is an instance of Node, which means that it
+        // has the "ownerDocument" property from which we can retrieve a
+        // corresponding global object.
+        var ownerGlobal = target && target.ownerDocument && target.ownerDocument.defaultView;
+        // Return the local global object if it's not possible extract one from
+        // provided element.
+        return ownerGlobal || global$1;
+    });
+
+    // Placeholder of an empty content rectangle.
+    var emptyRect = createRectInit(0, 0, 0, 0);
+    /**
+     * Converts provided string to a number.
+     *
+     * @param {number|string} value
+     * @returns {number}
+     */
+    function toFloat(value) {
+        return parseFloat(value) || 0;
+    }
+    /**
+     * Extracts borders size from provided styles.
+     *
+     * @param {CSSStyleDeclaration} styles
+     * @param {...string} positions - Borders positions (top, right, ...)
+     * @returns {number}
+     */
+    function getBordersSize(styles) {
+        var positions = [];
+        for (var _i = 1; _i < arguments.length; _i++) {
+            positions[_i - 1] = arguments[_i];
+        }
+        return positions.reduce(function (size, position) {
+            var value = styles['border-' + position + '-width'];
+            return size + toFloat(value);
+        }, 0);
+    }
+    /**
+     * Extracts paddings sizes from provided styles.
+     *
+     * @param {CSSStyleDeclaration} styles
+     * @returns {Object} Paddings box.
+     */
+    function getPaddings(styles) {
+        var positions = ['top', 'right', 'bottom', 'left'];
+        var paddings = {};
+        for (var _i = 0, positions_1 = positions; _i < positions_1.length; _i++) {
+            var position = positions_1[_i];
+            var value = styles['padding-' + position];
+            paddings[position] = toFloat(value);
+        }
+        return paddings;
+    }
+    /**
+     * Calculates content rectangle of provided SVG element.
+     *
+     * @param {SVGGraphicsElement} target - Element content rectangle of which needs
+     *      to be calculated.
+     * @returns {DOMRectInit}
+     */
+    function getSVGContentRect(target) {
+        var bbox = target.getBBox();
+        return createRectInit(0, 0, bbox.width, bbox.height);
+    }
+    /**
+     * Calculates content rectangle of provided HTMLElement.
+     *
+     * @param {HTMLElement} target - Element for which to calculate the content rectangle.
+     * @returns {DOMRectInit}
+     */
+    function getHTMLElementContentRect(target) {
+        // Client width & height properties can't be
+        // used exclusively as they provide rounded values.
+        var clientWidth = target.clientWidth, clientHeight = target.clientHeight;
+        // By this condition we can catch all non-replaced inline, hidden and
+        // detached elements. Though elements with width & height properties less
+        // than 0.5 will be discarded as well.
+        //
+        // Without it we would need to implement separate methods for each of
+        // those cases and it's not possible to perform a precise and performance
+        // effective test for hidden elements. E.g. even jQuery's ':visible' filter
+        // gives wrong results for elements with width & height less than 0.5.
+        if (!clientWidth && !clientHeight) {
+            return emptyRect;
+        }
+        var styles = getWindowOf(target).getComputedStyle(target);
+        var paddings = getPaddings(styles);
+        var horizPad = paddings.left + paddings.right;
+        var vertPad = paddings.top + paddings.bottom;
+        // Computed styles of width & height are being used because they are the
+        // only dimensions available to JS that contain non-rounded values. It could
+        // be possible to utilize the getBoundingClientRect if only it's data wasn't
+        // affected by CSS transformations let alone paddings, borders and scroll bars.
+        var width = toFloat(styles.width), height = toFloat(styles.height);
+        // Width & height include paddings and borders when the 'border-box' box
+        // model is applied (except for IE).
+        if (styles.boxSizing === 'border-box') {
+            // Following conditions are required to handle Internet Explorer which
+            // doesn't include paddings and borders to computed CSS dimensions.
+            //
+            // We can say that if CSS dimensions + paddings are equal to the "client"
+            // properties then it's either IE, and thus we don't need to subtract
+            // anything, or an element merely doesn't have paddings/borders styles.
+            if (Math.round(width + horizPad) !== clientWidth) {
+                width -= getBordersSize(styles, 'left', 'right') + horizPad;
+            }
+            if (Math.round(height + vertPad) !== clientHeight) {
+                height -= getBordersSize(styles, 'top', 'bottom') + vertPad;
+            }
+        }
+        // Following steps can't be applied to the document's root element as its
+        // client[Width/Height] properties represent viewport area of the window.
+        // Besides, it's as well not necessary as the <html> itself neither has
+        // rendered scroll bars nor it can be clipped.
+        if (!isDocumentElement(target)) {
+            // In some browsers (only in Firefox, actually) CSS width & height
+            // include scroll bars size which can be removed at this step as scroll
+            // bars are the only difference between rounded dimensions + paddings
+            // and "client" properties, though that is not always true in Chrome.
+            var vertScrollbar = Math.round(width + horizPad) - clientWidth;
+            var horizScrollbar = Math.round(height + vertPad) - clientHeight;
+            // Chrome has a rather weird rounding of "client" properties.
+            // E.g. for an element with content width of 314.2px it sometimes gives
+            // the client width of 315px and for the width of 314.7px it may give
+            // 314px. And it doesn't happen all the time. So just ignore this delta
+            // as a non-relevant.
+            if (Math.abs(vertScrollbar) !== 1) {
+                width -= vertScrollbar;
+            }
+            if (Math.abs(horizScrollbar) !== 1) {
+                height -= horizScrollbar;
+            }
+        }
+        return createRectInit(paddings.left, paddings.top, width, height);
+    }
+    /**
+     * Checks whether provided element is an instance of the SVGGraphicsElement.
+     *
+     * @param {Element} target - Element to be checked.
+     * @returns {boolean}
+     */
+    var isSVGGraphicsElement = (function () {
+        // Some browsers, namely IE and Edge, don't have the SVGGraphicsElement
+        // interface.
+        if (typeof SVGGraphicsElement !== 'undefined') {
+            return function (target) { return target instanceof getWindowOf(target).SVGGraphicsElement; };
+        }
+        // If it's so, then check that element is at least an instance of the
+        // SVGElement and that it has the "getBBox" method.
+        // eslint-disable-next-line no-extra-parens
+        return function (target) { return (target instanceof getWindowOf(target).SVGElement &&
+            typeof target.getBBox === 'function'); };
+    })();
+    /**
+     * Checks whether provided element is a document element (<html>).
+     *
+     * @param {Element} target - Element to be checked.
+     * @returns {boolean}
+     */
+    function isDocumentElement(target) {
+        return target === getWindowOf(target).document.documentElement;
+    }
+    /**
+     * Calculates an appropriate content rectangle for provided html or svg element.
+     *
+     * @param {Element} target - Element content rectangle of which needs to be calculated.
+     * @returns {DOMRectInit}
+     */
+    function getContentRect(target) {
+        if (!isBrowser) {
+            return emptyRect;
+        }
+        if (isSVGGraphicsElement(target)) {
+            return getSVGContentRect(target);
+        }
+        return getHTMLElementContentRect(target);
+    }
+    /**
+     * Creates rectangle with an interface of the DOMRectReadOnly.
+     * Spec: https://drafts.fxtf.org/geometry/#domrectreadonly
+     *
+     * @param {DOMRectInit} rectInit - Object with rectangle's x/y coordinates and dimensions.
+     * @returns {DOMRectReadOnly}
+     */
+    function createReadOnlyRect(_a) {
+        var x = _a.x, y = _a.y, width = _a.width, height = _a.height;
+        // If DOMRectReadOnly is available use it as a prototype for the rectangle.
+        var Constr = typeof DOMRectReadOnly !== 'undefined' ? DOMRectReadOnly : Object;
+        var rect = Object.create(Constr.prototype);
+        // Rectangle's properties are not writable and non-enumerable.
+        defineConfigurable(rect, {
+            x: x, y: y, width: width, height: height,
+            top: y,
+            right: x + width,
+            bottom: height + y,
+            left: x
+        });
+        return rect;
+    }
+    /**
+     * Creates DOMRectInit object based on the provided dimensions and the x/y coordinates.
+     * Spec: https://drafts.fxtf.org/geometry/#dictdef-domrectinit
+     *
+     * @param {number} x - X coordinate.
+     * @param {number} y - Y coordinate.
+     * @param {number} width - Rectangle's width.
+     * @param {number} height - Rectangle's height.
+     * @returns {DOMRectInit}
+     */
+    function createRectInit(x, y, width, height) {
+        return { x: x, y: y, width: width, height: height };
+    }
+
+    /**
+     * Class that is responsible for computations of the content rectangle of
+     * provided DOM element and for keeping track of it's changes.
+     */
+    var ResizeObservation = /** @class */ (function () {
+        /**
+         * Creates an instance of ResizeObservation.
+         *
+         * @param {Element} target - Element to be observed.
+         */
+        function ResizeObservation(target) {
+            /**
+             * Broadcasted width of content rectangle.
+             *
+             * @type {number}
+             */
+            this.broadcastWidth = 0;
+            /**
+             * Broadcasted height of content rectangle.
+             *
+             * @type {number}
+             */
+            this.broadcastHeight = 0;
+            /**
+             * Reference to the last observed content rectangle.
+             *
+             * @private {DOMRectInit}
+             */
+            this.contentRect_ = createRectInit(0, 0, 0, 0);
+            this.target = target;
+        }
+        /**
+         * Updates content rectangle and tells whether it's width or height properties
+         * have changed since the last broadcast.
+         *
+         * @returns {boolean}
+         */
+        ResizeObservation.prototype.isActive = function () {
+            var rect = getContentRect(this.target);
+            this.contentRect_ = rect;
+            return (rect.width !== this.broadcastWidth ||
+                rect.height !== this.broadcastHeight);
+        };
+        /**
+         * Updates 'broadcastWidth' and 'broadcastHeight' properties with a data
+         * from the corresponding properties of the last observed content rectangle.
+         *
+         * @returns {DOMRectInit} Last observed content rectangle.
+         */
+        ResizeObservation.prototype.broadcastRect = function () {
+            var rect = this.contentRect_;
+            this.broadcastWidth = rect.width;
+            this.broadcastHeight = rect.height;
+            return rect;
+        };
+        return ResizeObservation;
+    }());
+
+    var ResizeObserverEntry = /** @class */ (function () {
+        /**
+         * Creates an instance of ResizeObserverEntry.
+         *
+         * @param {Element} target - Element that is being observed.
+         * @param {DOMRectInit} rectInit - Data of the element's content rectangle.
+         */
+        function ResizeObserverEntry(target, rectInit) {
+            var contentRect = createReadOnlyRect(rectInit);
+            // According to the specification following properties are not writable
+            // and are also not enumerable in the native implementation.
+            //
+            // Property accessors are not being used as they'd require to define a
+            // private WeakMap storage which may cause memory leaks in browsers that
+            // don't support this type of collections.
+            defineConfigurable(this, { target: target, contentRect: contentRect });
+        }
+        return ResizeObserverEntry;
+    }());
+
+    var ResizeObserverSPI = /** @class */ (function () {
+        /**
+         * Creates a new instance of ResizeObserver.
+         *
+         * @param {ResizeObserverCallback} callback - Callback function that is invoked
+         *      when one of the observed elements changes it's content dimensions.
+         * @param {ResizeObserverController} controller - Controller instance which
+         *      is responsible for the updates of observer.
+         * @param {ResizeObserver} callbackCtx - Reference to the public
+         *      ResizeObserver instance which will be passed to callback function.
+         */
+        function ResizeObserverSPI(callback, controller, callbackCtx) {
+            /**
+             * Collection of resize observations that have detected changes in dimensions
+             * of elements.
+             *
+             * @private {Array<ResizeObservation>}
+             */
+            this.activeObservations_ = [];
+            /**
+             * Registry of the ResizeObservation instances.
+             *
+             * @private {Map<Element, ResizeObservation>}
+             */
+            this.observations_ = new MapShim();
+            if (typeof callback !== 'function') {
+                throw new TypeError('The callback provided as parameter 1 is not a function.');
+            }
+            this.callback_ = callback;
+            this.controller_ = controller;
+            this.callbackCtx_ = callbackCtx;
+        }
+        /**
+         * Starts observing provided element.
+         *
+         * @param {Element} target - Element to be observed.
+         * @returns {void}
+         */
+        ResizeObserverSPI.prototype.observe = function (target) {
+            if (!arguments.length) {
+                throw new TypeError('1 argument required, but only 0 present.');
+            }
+            // Do nothing if current environment doesn't have the Element interface.
+            if (typeof Element === 'undefined' || !(Element instanceof Object)) {
+                return;
+            }
+            if (!(target instanceof getWindowOf(target).Element)) {
+                throw new TypeError('parameter 1 is not of type "Element".');
+            }
+            var observations = this.observations_;
+            // Do nothing if element is already being observed.
+            if (observations.has(target)) {
+                return;
+            }
+            observations.set(target, new ResizeObservation(target));
+            this.controller_.addObserver(this);
+            // Force the update of observations.
+            this.controller_.refresh();
+        };
+        /**
+         * Stops observing provided element.
+         *
+         * @param {Element} target - Element to stop observing.
+         * @returns {void}
+         */
+        ResizeObserverSPI.prototype.unobserve = function (target) {
+            if (!arguments.length) {
+                throw new TypeError('1 argument required, but only 0 present.');
+            }
+            // Do nothing if current environment doesn't have the Element interface.
+            if (typeof Element === 'undefined' || !(Element instanceof Object)) {
+                return;
+            }
+            if (!(target instanceof getWindowOf(target).Element)) {
+                throw new TypeError('parameter 1 is not of type "Element".');
+            }
+            var observations = this.observations_;
+            // Do nothing if element is not being observed.
+            if (!observations.has(target)) {
+                return;
+            }
+            observations.delete(target);
+            if (!observations.size) {
+                this.controller_.removeObserver(this);
+            }
+        };
+        /**
+         * Stops observing all elements.
+         *
+         * @returns {void}
+         */
+        ResizeObserverSPI.prototype.disconnect = function () {
+            this.clearActive();
+            this.observations_.clear();
+            this.controller_.removeObserver(this);
+        };
+        /**
+         * Collects observation instances the associated element of which has changed
+         * it's content rectangle.
+         *
+         * @returns {void}
+         */
+        ResizeObserverSPI.prototype.gatherActive = function () {
+            var _this = this;
+            this.clearActive();
+            this.observations_.forEach(function (observation) {
+                if (observation.isActive()) {
+                    _this.activeObservations_.push(observation);
+                }
+            });
+        };
+        /**
+         * Invokes initial callback function with a list of ResizeObserverEntry
+         * instances collected from active resize observations.
+         *
+         * @returns {void}
+         */
+        ResizeObserverSPI.prototype.broadcastActive = function () {
+            // Do nothing if observer doesn't have active observations.
+            if (!this.hasActive()) {
+                return;
+            }
+            var ctx = this.callbackCtx_;
+            // Create ResizeObserverEntry instance for every active observation.
+            var entries = this.activeObservations_.map(function (observation) {
+                return new ResizeObserverEntry(observation.target, observation.broadcastRect());
+            });
+            this.callback_.call(ctx, entries, ctx);
+            this.clearActive();
+        };
+        /**
+         * Clears the collection of active observations.
+         *
+         * @returns {void}
+         */
+        ResizeObserverSPI.prototype.clearActive = function () {
+            this.activeObservations_.splice(0);
+        };
+        /**
+         * Tells whether observer has active observations.
+         *
+         * @returns {boolean}
+         */
+        ResizeObserverSPI.prototype.hasActive = function () {
+            return this.activeObservations_.length > 0;
+        };
+        return ResizeObserverSPI;
+    }());
+
+    // Registry of internal observers. If WeakMap is not available use current shim
+    // for the Map collection as it has all required methods and because WeakMap
+    // can't be fully polyfilled anyway.
+    var observers = typeof WeakMap !== 'undefined' ? new WeakMap() : new MapShim();
+    /**
+     * ResizeObserver API. Encapsulates the ResizeObserver SPI implementation
+     * exposing only those methods and properties that are defined in the spec.
+     */
+    var ResizeObserver = /** @class */ (function () {
+        /**
+         * Creates a new instance of ResizeObserver.
+         *
+         * @param {ResizeObserverCallback} callback - Callback that is invoked when
+         *      dimensions of the observed elements change.
+         */
+        function ResizeObserver(callback) {
+            if (!(this instanceof ResizeObserver)) {
+                throw new TypeError('Cannot call a class as a function.');
+            }
+            if (!arguments.length) {
+                throw new TypeError('1 argument required, but only 0 present.');
+            }
+            var controller = ResizeObserverController.getInstance();
+            var observer = new ResizeObserverSPI(callback, controller, this);
+            observers.set(this, observer);
+        }
+        return ResizeObserver;
+    }());
+    // Expose public methods of ResizeObserver.
+    [
+        'observe',
+        'unobserve',
+        'disconnect'
+    ].forEach(function (method) {
+        ResizeObserver.prototype[method] = function () {
+            var _a;
+            return (_a = observers.get(this))[method].apply(_a, arguments);
+        };
+    });
+
+    var index = (function () {
+        // Export existing implementation if available.
+        if (typeof global$1.ResizeObserver !== 'undefined') {
+            return global$1.ResizeObserver;
+        }
+        return ResizeObserver;
+    })();
+
+    return index;
+
+})));

node_modules/resize-observer-polyfill/dist/ResizeObserver.js.flow

@@ -0,0 +1,32 @@
+// @flow
+
+class DOMRectReadOnly {
+    +x: number;
+    +y: number;
+    +width: number;
+    +height: number;
+    +top: number;
+    +right: number;
+    +bottom: number;
+    +left: number;
+}
+
+class ResizeObserverEntry {
+    +target: Element;
+    +contentRect: DOMRectReadOnly;
+}
+
+type Entries = $ReadOnlyArray<ResizeObserverEntry>;
+
+type ResizeObserverCallback = {
+    (entries: Entries, observer: ResizeObserver): void
+};
+
+declare class ResizeObserver {
+    constructor(ResizeObserverCallback): ResizeObserver;
+    observe(target: Element): void;
+    unobserve(target: Element): void;
+    disconnect(): void;
+};
+
+declare export default typeof ResizeObserver;

node_modules/resize-observer-polyfill/package.json

@@ -0,0 +1,64 @@
+{
+    "name": "resize-observer-polyfill",
+    "author": "Denis Rul <que.etc@gmail.com>",
+    "version": "1.5.1",
+    "description": "A polyfill for the Resize Observer API",
+    "main": "dist/ResizeObserver.js",
+    "module": "dist/ResizeObserver.es.js",
+    "scripts": {
+        "build": "rollup -c && cpy src/index.js.flow dist --rename=ResizeObserver.js.flow",
+        "test": "npm run test:lint && npm run test:spec",
+        "test:ci": "npm run test:lint && npm run test:spec:sauce && npm run test:spec:node",
+        "test:ci:pull": "npm run test:lint && karma start --browsers Firefox && npm run test:spec:node",
+        "test:lint": "node ./node_modules/eslint/bin/eslint.js \"**/*.js\" --ignore-pattern \"/dist/\"",
+        "test:spec": "karma start --browsers Chrome && npm run test:spec:node",
+        "test:spec:sauce": "karma start --sauce=windows && karma start --sauce=linux && karma start --sauce=osx",
+        "test:spec:node": "npm run build && node tests/node/index.js",
+        "test:spec:custom": "karma start --no-browsers",
+        "test:spec:native": "karma start --no-browsers --native"
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/que-etc/resize-observer-polyfill.git"
+    },
+    "license": "MIT",
+    "bugs": {
+        "url": "https://github.com/que-etc/resize-observer-polyfill/issues"
+    },
+    "types": "src/index.d.ts",
+    "files": [
+        "src/",
+        "dist/"
+    ],
+    "keywords": [
+        "ResizeObserver",
+        "resize",
+        "observer",
+        "util",
+        "client",
+        "browser",
+        "polyfill",
+        "ponyfill"
+    ],
+    "homepage": "https://github.com/que-etc/resize-observer-polyfill",
+    "devDependencies": {
+        "babel-eslint": "10.0.1",
+        "cpy-cli": "2.0.0",
+        "eslint": "5.10.0",
+        "jasmine": "2.8.0",
+        "jasmine-core": "2.8.0",
+        "karma": "3.1.3",
+        "karma-chrome-launcher": "2.2.0",
+        "karma-firefox-launcher": "1.1.0",
+        "karma-jasmine": "1.1.2",
+        "karma-jasmine-html-reporter": "0.2.2",
+        "karma-rollup-preprocessor": "6.1.1",
+        "karma-sauce-launcher": "1.2.0",
+        "karma-sourcemap-loader": "0.3.7",
+        "karma-spec-reporter": "0.0.32",
+        "promise-polyfill": "8.1.0",
+        "rollup": "0.67.4",
+        "rollup-plugin-typescript": "1.0.0",
+        "typescript": "3.2.2"
+    }
+}

node_modules/resize-observer-polyfill/src/ResizeObservation.js

@@ -0,0 +1,76 @@
+import {createRectInit, getContentRect} from './utils/geometry.js';
+
+/**
+ * Class that is responsible for computations of the content rectangle of
+ * provided DOM element and for keeping track of it's changes.
+ */
+export default class ResizeObservation {
+    /**
+     * Reference to the observed element.
+     *
+     * @type {Element}
+     */
+    target;
+
+    /**
+     * Broadcasted width of content rectangle.
+     *
+     * @type {number}
+     */
+    broadcastWidth = 0;
+
+    /**
+     * Broadcasted height of content rectangle.
+     *
+     * @type {number}
+     */
+    broadcastHeight = 0;
+
+    /**
+     * Reference to the last observed content rectangle.
+     *
+     * @private {DOMRectInit}
+     */
+    contentRect_ = createRectInit(0, 0, 0, 0);
+
+    /**
+     * Creates an instance of ResizeObservation.
+     *
+     * @param {Element} target - Element to be observed.
+     */
+    constructor(target) {
+        this.target = target;
+    }
+
+    /**
+     * Updates content rectangle and tells whether it's width or height properties
+     * have changed since the last broadcast.
+     *
+     * @returns {boolean}
+     */
+    isActive() {
+        const rect = getContentRect(this.target);
+
+        this.contentRect_ = rect;
+
+        return (
+            rect.width !== this.broadcastWidth ||
+            rect.height !== this.broadcastHeight
+        );
+    }
+
+    /**
+     * Updates 'broadcastWidth' and 'broadcastHeight' properties with a data
+     * from the corresponding properties of the last observed content rectangle.
+     *
+     * @returns {DOMRectInit} Last observed content rectangle.
+     */
+    broadcastRect() {
+        const rect = this.contentRect_;
+
+        this.broadcastWidth = rect.width;
+        this.broadcastHeight = rect.height;
+
+        return rect;
+    }
+}

node_modules/resize-observer-polyfill/src/ResizeObserver.js

@@ -0,0 +1,47 @@
+import {Map} from './shims/es6-collections.js';
+import ResizeObserverController from './ResizeObserverController.js';
+import ResizeObserverSPI from './ResizeObserverSPI.js';
+
+// Registry of internal observers. If WeakMap is not available use current shim
+// for the Map collection as it has all required methods and because WeakMap
+// can't be fully polyfilled anyway.
+const observers = typeof WeakMap !== 'undefined' ? new WeakMap() : new Map();
+
+/**
+ * ResizeObserver API. Encapsulates the ResizeObserver SPI implementation
+ * exposing only those methods and properties that are defined in the spec.
+ */
+class ResizeObserver {
+    /**
+     * Creates a new instance of ResizeObserver.
+     *
+     * @param {ResizeObserverCallback} callback - Callback that is invoked when
+     *      dimensions of the observed elements change.
+     */
+    constructor(callback) {
+        if (!(this instanceof ResizeObserver)) {
+            throw new TypeError('Cannot call a class as a function.');
+        }
+        if (!arguments.length) {
+            throw new TypeError('1 argument required, but only 0 present.');
+        }
+
+        const controller = ResizeObserverController.getInstance();
+        const observer = new ResizeObserverSPI(callback, controller, this);
+
+        observers.set(this, observer);
+    }
+}
+
+// Expose public methods of ResizeObserver.
+[
+    'observe',
+    'unobserve',
+    'disconnect'
+].forEach(method => {
+    ResizeObserver.prototype[method] = function () {
+        return observers.get(this)[method](...arguments);
+    };
+});
+
+export default ResizeObserver;

node_modules/resize-observer-polyfill/src/ResizeObserverController.js

@@ -0,0 +1,238 @@
+import isBrowser from './utils/isBrowser.js';
+import throttle from './utils/throttle.js';
+
+// Minimum delay before invoking the update of observers.
+const REFRESH_DELAY = 20;
+
+// A list of substrings of CSS properties used to find transition events that
+// might affect dimensions of observed elements.
+const transitionKeys = ['top', 'right', 'bottom', 'left', 'width', 'height', 'size', 'weight'];
+
+// Check if MutationObserver is available.
+const mutationObserverSupported = typeof MutationObserver !== 'undefined';
+
+/**
+ * Singleton controller class which handles updates of ResizeObserver instances.
+ */
+export default class ResizeObserverController {
+    /**
+     * Indicates whether DOM listeners have been added.
+     *
+     * @private {boolean}
+     */
+    connected_ = false;
+
+    /**
+     * Tells that controller has subscribed for Mutation Events.
+     *
+     * @private {boolean}
+     */
+    mutationEventsAdded_ = false;
+
+    /**
+     * Keeps reference to the instance of MutationObserver.
+     *
+     * @private {MutationObserver}
+     */
+    mutationsObserver_ = null;
+
+    /**
+     * A list of connected observers.
+     *
+     * @private {Array<ResizeObserverSPI>}
+     */
+    observers_ = [];
+
+    /**
+     * Holds reference to the controller's instance.
+     *
+     * @private {ResizeObserverController}
+     */
+    static instance_ = null;
+
+    /**
+     * Creates a new instance of ResizeObserverController.
+     *
+     * @private
+     */
+    constructor() {
+        this.onTransitionEnd_ = this.onTransitionEnd_.bind(this);
+        this.refresh = throttle(this.refresh.bind(this), REFRESH_DELAY);
+    }
+
+    /**
+     * Adds observer to observers list.
+     *
+     * @param {ResizeObserverSPI} observer - Observer to be added.
+     * @returns {void}
+     */
+    addObserver(observer) {
+        if (!~this.observers_.indexOf(observer)) {
+            this.observers_.push(observer);
+        }
+
+        // Add listeners if they haven't been added yet.
+        if (!this.connected_) {
+            this.connect_();
+        }
+    }
+
+    /**
+     * Removes observer from observers list.
+     *
+     * @param {ResizeObserverSPI} observer - Observer to be removed.
+     * @returns {void}
+     */
+    removeObserver(observer) {
+        const observers = this.observers_;
+        const index = observers.indexOf(observer);
+
+        // Remove observer if it's present in registry.
+        if (~index) {
+            observers.splice(index, 1);
+        }
+
+        // Remove listeners if controller has no connected observers.
+        if (!observers.length && this.connected_) {
+            this.disconnect_();
+        }
+    }
+
+    /**
+     * Invokes the update of observers. It will continue running updates insofar
+     * it detects changes.
+     *
+     * @returns {void}
+     */
+    refresh() {
+        const changesDetected = this.updateObservers_();
+
+        // Continue running updates if changes have been detected as there might
+        // be future ones caused by CSS transitions.
+        if (changesDetected) {
+            this.refresh();
+        }
+    }
+
+    /**
+     * Updates every observer from observers list and notifies them of queued
+     * entries.
+     *
+     * @private
+     * @returns {boolean} Returns "true" if any observer has detected changes in
+     *      dimensions of it's elements.
+     */
+    updateObservers_() {
+        // Collect observers that have active observations.
+        const activeObservers = this.observers_.filter(observer => {
+            return observer.gatherActive(), observer.hasActive();
+        });
+
+        // Deliver notifications in a separate cycle in order to avoid any
+        // collisions between observers, e.g. when multiple instances of
+        // ResizeObserver are tracking the same element and the callback of one
+        // of them changes content dimensions of the observed target. Sometimes
+        // this may result in notifications being blocked for the rest of observers.
+        activeObservers.forEach(observer => observer.broadcastActive());
+
+        return activeObservers.length > 0;
+    }
+
+    /**
+     * Initializes DOM listeners.
+     *
+     * @private
+     * @returns {void}
+     */
+    connect_() {
+        // Do nothing if running in a non-browser environment or if listeners
+        // have been already added.
+        if (!isBrowser || this.connected_) {
+            return;
+        }
+
+        // Subscription to the "Transitionend" event is used as a workaround for
+        // delayed transitions. This way it's possible to capture at least the
+        // final state of an element.
+        document.addEventListener('transitionend', this.onTransitionEnd_);
+
+        window.addEventListener('resize', this.refresh);
+
+        if (mutationObserverSupported) {
+            this.mutationsObserver_ = new MutationObserver(this.refresh);
+
+            this.mutationsObserver_.observe(document, {
+                attributes: true,
+                childList: true,
+                characterData: true,
+                subtree: true
+            });
+        } else {
+            document.addEventListener('DOMSubtreeModified', this.refresh);
+
+            this.mutationEventsAdded_ = true;
+        }
+
+        this.connected_ = true;
+    }
+
+    /**
+     * Removes DOM listeners.
+     *
+     * @private
+     * @returns {void}
+     */
+    disconnect_() {
+        // Do nothing if running in a non-browser environment or if listeners
+        // have been already removed.
+        if (!isBrowser || !this.connected_) {
+            return;
+        }
+
+        document.removeEventListener('transitionend', this.onTransitionEnd_);
+        window.removeEventListener('resize', this.refresh);
+
+        if (this.mutationsObserver_) {
+            this.mutationsObserver_.disconnect();
+        }
+
+        if (this.mutationEventsAdded_) {
+            document.removeEventListener('DOMSubtreeModified', this.refresh);
+        }
+
+        this.mutationsObserver_ = null;
+        this.mutationEventsAdded_ = false;
+        this.connected_ = false;
+    }
+
+    /**
+     * "Transitionend" event handler.
+     *
+     * @private
+     * @param {TransitionEvent} event
+     * @returns {void}
+     */
+    onTransitionEnd_({propertyName = ''}) {
+        // Detect whether transition may affect dimensions of an element.
+        const isReflowProperty = transitionKeys.some(key => {
+            return !!~propertyName.indexOf(key);
+        });
+
+        if (isReflowProperty) {
+            this.refresh();
+        }
+    }
+
+    /**
+     * Returns instance of the ResizeObserverController.
+     *
+     * @returns {ResizeObserverController}
+     */
+    static getInstance() {
+        if (!this.instance_) {
+            this.instance_ = new ResizeObserverController();
+        }
+
+        return this.instance_;
+    }
+}

node_modules/resize-observer-polyfill/src/ResizeObserverEntry.js

@@ -0,0 +1,40 @@
+import {createReadOnlyRect} from './utils/geometry.js';
+import defineConfigurable from './utils/defineConfigurable.js';
+
+export default class ResizeObserverEntry {
+    /**
+     * Element size of which has changed.
+     * Spec: https://wicg.github.io/ResizeObserver/#dom-resizeobserverentry-target
+     *
+     * @readonly
+     * @type {Element}
+     */
+    target;
+
+    /**
+     * Element's content rectangle.
+     * Spec: https://wicg.github.io/ResizeObserver/#dom-resizeobserverentry-contentrect
+     *
+     * @readonly
+     * @type {DOMRectReadOnly}
+     */
+    contentRect;
+
+    /**
+     * Creates an instance of ResizeObserverEntry.
+     *
+     * @param {Element} target - Element that is being observed.
+     * @param {DOMRectInit} rectInit - Data of the element's content rectangle.
+     */
+    constructor(target, rectInit) {
+        const contentRect = createReadOnlyRect(rectInit);
+
+        // According to the specification following properties are not writable
+        // and are also not enumerable in the native implementation.
+        //
+        // Property accessors are not being used as they'd require to define a
+        // private WeakMap storage which may cause memory leaks in browsers that
+        // don't support this type of collections.
+        defineConfigurable(this, {target, contentRect});
+    }
+}

node_modules/resize-observer-polyfill/src/ResizeObserverSPI.js

@@ -0,0 +1,203 @@
+import {Map} from './shims/es6-collections.js';
+import ResizeObservation from './ResizeObservation.js';
+import ResizeObserverEntry from './ResizeObserverEntry.js';
+import getWindowOf from './utils/getWindowOf.js';
+
+export default class ResizeObserverSPI {
+    /**
+     * Collection of resize observations that have detected changes in dimensions
+     * of elements.
+     *
+     * @private {Array<ResizeObservation>}
+     */
+    activeObservations_ = [];
+
+    /**
+     * Reference to the callback function.
+     *
+     * @private {ResizeObserverCallback}
+     */
+    callback_;
+
+    /**
+     * Public ResizeObserver instance which will be passed to the callback
+     * function and used as a value of it's "this" binding.
+     *
+     * @private {ResizeObserver}
+     */
+    callbackCtx_;
+
+    /**
+     * Reference to the associated ResizeObserverController.
+     *
+     * @private {ResizeObserverController}
+     */
+    controller_;
+
+    /**
+     * Registry of the ResizeObservation instances.
+     *
+     * @private {Map<Element, ResizeObservation>}
+     */
+    observations_ = new Map();
+
+    /**
+     * Creates a new instance of ResizeObserver.
+     *
+     * @param {ResizeObserverCallback} callback - Callback function that is invoked
+     *      when one of the observed elements changes it's content dimensions.
+     * @param {ResizeObserverController} controller - Controller instance which
+     *      is responsible for the updates of observer.
+     * @param {ResizeObserver} callbackCtx - Reference to the public
+     *      ResizeObserver instance which will be passed to callback function.
+     */
+    constructor(callback, controller, callbackCtx) {
+        if (typeof callback !== 'function') {
+            throw new TypeError('The callback provided as parameter 1 is not a function.');
+        }
+
+        this.callback_ = callback;
+        this.controller_ = controller;
+        this.callbackCtx_ = callbackCtx;
+    }
+
+    /**
+     * Starts observing provided element.
+     *
+     * @param {Element} target - Element to be observed.
+     * @returns {void}
+     */
+    observe(target) {
+        if (!arguments.length) {
+            throw new TypeError('1 argument required, but only 0 present.');
+        }
+
+        // Do nothing if current environment doesn't have the Element interface.
+        if (typeof Element === 'undefined' || !(Element instanceof Object)) {
+            return;
+        }
+
+        if (!(target instanceof getWindowOf(target).Element)) {
+            throw new TypeError('parameter 1 is not of type "Element".');
+        }
+
+        const observations = this.observations_;
+
+        // Do nothing if element is already being observed.
+        if (observations.has(target)) {
+            return;
+        }
+
+        observations.set(target, new ResizeObservation(target));
+
+        this.controller_.addObserver(this);
+
+        // Force the update of observations.
+        this.controller_.refresh();
+    }
+
+    /**
+     * Stops observing provided element.
+     *
+     * @param {Element} target - Element to stop observing.
+     * @returns {void}
+     */
+    unobserve(target) {
+        if (!arguments.length) {
+            throw new TypeError('1 argument required, but only 0 present.');
+        }
+
+        // Do nothing if current environment doesn't have the Element interface.
+        if (typeof Element === 'undefined' || !(Element instanceof Object)) {
+            return;
+        }
+
+        if (!(target instanceof getWindowOf(target).Element)) {
+            throw new TypeError('parameter 1 is not of type "Element".');
+        }
+
+        const observations = this.observations_;
+
+        // Do nothing if element is not being observed.
+        if (!observations.has(target)) {
+            return;
+        }
+
+        observations.delete(target);
+
+        if (!observations.size) {
+            this.controller_.removeObserver(this);
+        }
+    }
+
+    /**
+     * Stops observing all elements.
+     *
+     * @returns {void}
+     */
+    disconnect() {
+        this.clearActive();
+        this.observations_.clear();
+        this.controller_.removeObserver(this);
+    }
+
+    /**
+     * Collects observation instances the associated element of which has changed
+     * it's content rectangle.
+     *
+     * @returns {void}
+     */
+    gatherActive() {
+        this.clearActive();
+
+        this.observations_.forEach(observation => {
+            if (observation.isActive()) {
+                this.activeObservations_.push(observation);
+            }
+        });
+    }
+
+    /**
+     * Invokes initial callback function with a list of ResizeObserverEntry
+     * instances collected from active resize observations.
+     *
+     * @returns {void}
+     */
+    broadcastActive() {
+        // Do nothing if observer doesn't have active observations.
+        if (!this.hasActive()) {
+            return;
+        }
+
+        const ctx = this.callbackCtx_;
+
+        // Create ResizeObserverEntry instance for every active observation.
+        const entries = this.activeObservations_.map(observation => {
+            return new ResizeObserverEntry(
+                observation.target,
+                observation.broadcastRect()
+            );
+        });
+
+        this.callback_.call(ctx, entries, ctx);
+        this.clearActive();
+    }
+
+    /**
+     * Clears the collection of active observations.
+     *
+     * @returns {void}
+     */
+    clearActive() {
+        this.activeObservations_.splice(0);
+    }
+
+    /**
+     * Tells whether observer has active observations.
+     *
+     * @returns {boolean}
+     */
+    hasActive() {
+        return this.activeObservations_.length > 0;
+    }
+}

node_modules/resize-observer-polyfill/src/index.d.ts

@@ -0,0 +1,40 @@
+interface DOMRectReadOnly {
+    readonly x: number;
+    readonly y: number;
+    readonly width: number;
+    readonly height: number;
+    readonly top: number;
+    readonly right: number;
+    readonly bottom: number;
+    readonly left: number;
+}
+
+declare global {
+    interface ResizeObserverCallback {
+        (entries: ResizeObserverEntry[], observer: ResizeObserver): void
+    }
+
+    interface ResizeObserverEntry {
+        readonly target: Element;
+        readonly contentRect: DOMRectReadOnly;
+    }
+
+    interface ResizeObserver {
+        observe(target: Element): void;
+        unobserve(target: Element): void;
+        disconnect(): void;
+    }
+}
+
+declare var ResizeObserver: {
+    prototype: ResizeObserver;
+    new(callback: ResizeObserverCallback): ResizeObserver;
+}
+
+interface ResizeObserver {
+    observe(target: Element): void;
+    unobserve(target: Element): void;
+    disconnect(): void;
+}
+
+export default ResizeObserver;

node_modules/resize-observer-polyfill/src/index.js

@@ -0,0 +1,11 @@
+import ResizeObserverPolyfill from './ResizeObserver.js';
+import global from './shims/global.js';
+
+export default (() => {
+    // Export existing implementation if available.
+    if (typeof global.ResizeObserver !== 'undefined') {
+        return global.ResizeObserver;
+    }
+
+    return ResizeObserverPolyfill;
+})();

node_modules/resize-observer-polyfill/src/index.js.flow

@@ -0,0 +1,32 @@
+// @flow
+
+class DOMRectReadOnly {
+    +x: number;
+    +y: number;
+    +width: number;
+    +height: number;
+    +top: number;
+    +right: number;
+    +bottom: number;
+    +left: number;
+}
+
+class ResizeObserverEntry {
+    +target: Element;
+    +contentRect: DOMRectReadOnly;
+}
+
+type Entries = $ReadOnlyArray<ResizeObserverEntry>;
+
+type ResizeObserverCallback = {
+    (entries: Entries, observer: ResizeObserver): void
+};
+
+declare class ResizeObserver {
+    constructor(ResizeObserverCallback): ResizeObserver;
+    observe(target: Element): void;
+    unobserve(target: Element): void;
+    disconnect(): void;
+};
+
+declare export default typeof ResizeObserver;

node_modules/resize-observer-polyfill/src/shims/es6-collections.js

@@ -0,0 +1,115 @@
+/**
+ * A collection of shims that provide minimal functionality of the ES6 collections.
+ *
+ * These implementations are not meant to be used outside of the ResizeObserver
+ * modules as they cover only a limited range of use cases.
+ */
+/* eslint-disable require-jsdoc, valid-jsdoc */
+const MapShim = (() => {
+    if (typeof Map !== 'undefined') {
+        return Map;
+    }
+
+    /**
+     * Returns index in provided array that matches the specified key.
+     *
+     * @param {Array<Array>} arr
+     * @param {*} key
+     * @returns {number}
+     */
+    function getIndex(arr, key) {
+        let result = -1;
+
+        arr.some((entry, index) => {
+            if (entry[0] === key) {
+                result = index;
+
+                return true;
+            }
+
+            return false;
+        });
+
+        return result;
+    }
+
+    return class {
+        constructor() {
+            this.__entries__ = [];
+        }
+
+        /**
+         * @returns {boolean}
+         */
+        get size() {
+            return this.__entries__.length;
+        }
+
+        /**
+         * @param {*} key
+         * @returns {*}
+         */
+        get(key) {
+            const index = getIndex(this.__entries__, key);
+            const entry = this.__entries__[index];
+
+            return entry && entry[1];
+        }
+
+        /**
+         * @param {*} key
+         * @param {*} value
+         * @returns {void}
+         */
+        set(key, value) {
+            const index = getIndex(this.__entries__, key);
+
+            if (~index) {
+                this.__entries__[index][1] = value;
+            } else {
+                this.__entries__.push([key, value]);
+            }
+        }
+
+        /**
+         * @param {*} key
+         * @returns {void}
+         */
+        delete(key) {
+            const entries = this.__entries__;
+            const index = getIndex(entries, key);
+
+            if (~index) {
+                entries.splice(index, 1);
+            }
+        }
+
+        /**
+         * @param {*} key
+         * @returns {void}
+         */
+        has(key) {
+            return !!~getIndex(this.__entries__, key);
+        }
+
+        /**
+         * @returns {void}
+         */
+        clear() {
+            this.__entries__.splice(0);
+        }
+
+        /**
+         * @param {Function} callback
+         * @param {*} [ctx=null]
+         * @returns {void}
+         */
+        forEach(callback, ctx = null) {
+            for (const entry of this.__entries__) {
+                callback.call(ctx, entry[1], entry[0]);
+            }
+        }
+    };
+})();
+
+export {MapShim as Map};

node_modules/resize-observer-polyfill/src/shims/global.js

@@ -0,0 +1,17 @@
+// Returns global object of a current environment.
+export default (() => {
+    if (typeof global !== 'undefined' && global.Math === Math) {
+        return global;
+    }
+
+    if (typeof self !== 'undefined' && self.Math === Math) {
+        return self;
+    }
+
+    if (typeof window !== 'undefined' && window.Math === Math) {
+        return window;
+    }
+
+    // eslint-disable-next-line no-new-func
+    return Function('return this')();
+})();

node_modules/resize-observer-polyfill/src/shims/requestAnimationFrame.js

@@ -0,0 +1,18 @@
+import global from './global.js';
+
+/**
+ * A shim for the requestAnimationFrame which falls back to the setTimeout if
+ * first one is not supported.
+ *
+ * @returns {number} Requests' identifier.
+ */
+export default (() => {
+    if (typeof requestAnimationFrame === 'function') {
+        // It's required to use a bounded function because IE sometimes throws
+        // an "Invalid calling object" error if rAF is invoked without the global
+        // object on the left hand side.
+        return requestAnimationFrame.bind(global);
+    }
+
+    return callback => setTimeout(() => callback(Date.now()), 1000 / 60);
+})();

node_modules/resize-observer-polyfill/src/utils/defineConfigurable.js

@@ -0,0 +1,19 @@
+/**
+ * Defines non-writable/enumerable properties of the provided target object.
+ *
+ * @param {Object} target - Object for which to define properties.
+ * @param {Object} props - Properties to be defined.
+ * @returns {Object} Target object.
+ */
+export default (target, props) => {
+    for (const key of Object.keys(props)) {
+        Object.defineProperty(target, key, {
+            value: props[key],
+            enumerable: false,
+            writable: false,
+            configurable: true
+        });
+    }
+
+    return target;
+};

node_modules/resize-observer-polyfill/src/utils/geometry.js

@@ -0,0 +1,233 @@
+import defineConfigurable from './defineConfigurable.js';
+import getWindowOf from './getWindowOf.js';
+import isBrowser from './isBrowser.js';
+
+// Placeholder of an empty content rectangle.
+const emptyRect = createRectInit(0, 0, 0, 0);
+
+/**
+ * Converts provided string to a number.
+ *
+ * @param {number|string} value
+ * @returns {number}
+ */
+function toFloat(value) {
+    return parseFloat(value) || 0;
+}
+
+/**
+ * Extracts borders size from provided styles.
+ *
+ * @param {CSSStyleDeclaration} styles
+ * @param {...string} positions - Borders positions (top, right, ...)
+ * @returns {number}
+ */
+function getBordersSize(styles, ...positions) {
+    return positions.reduce((size, position) => {
+        const value = styles['border-' + position + '-width'];
+
+        return size + toFloat(value);
+    }, 0);
+}
+
+/**
+ * Extracts paddings sizes from provided styles.
+ *
+ * @param {CSSStyleDeclaration} styles
+ * @returns {Object} Paddings box.
+ */
+function getPaddings(styles) {
+    const positions = ['top', 'right', 'bottom', 'left'];
+    const paddings = {};
+
+    for (const position of positions) {
+        const value = styles['padding-' + position];
+
+        paddings[position] = toFloat(value);
+    }
+
+    return paddings;
+}
+
+/**
+ * Calculates content rectangle of provided SVG element.
+ *
+ * @param {SVGGraphicsElement} target - Element content rectangle of which needs
+ *      to be calculated.
+ * @returns {DOMRectInit}
+ */
+function getSVGContentRect(target) {
+    const bbox = target.getBBox();
+
+    return createRectInit(0, 0, bbox.width, bbox.height);
+}
+
+/**
+ * Calculates content rectangle of provided HTMLElement.
+ *
+ * @param {HTMLElement} target - Element for which to calculate the content rectangle.
+ * @returns {DOMRectInit}
+ */
+function getHTMLElementContentRect(target) {
+    // Client width & height properties can't be
+    // used exclusively as they provide rounded values.
+    const {clientWidth, clientHeight} = target;
+
+    // By this condition we can catch all non-replaced inline, hidden and
+    // detached elements. Though elements with width & height properties less
+    // than 0.5 will be discarded as well.
+    //
+    // Without it we would need to implement separate methods for each of
+    // those cases and it's not possible to perform a precise and performance
+    // effective test for hidden elements. E.g. even jQuery's ':visible' filter
+    // gives wrong results for elements with width & height less than 0.5.
+    if (!clientWidth && !clientHeight) {
+        return emptyRect;
+    }
+
+    const styles = getWindowOf(target).getComputedStyle(target);
+    const paddings = getPaddings(styles);
+    const horizPad = paddings.left + paddings.right;
+    const vertPad = paddings.top + paddings.bottom;
+
+    // Computed styles of width & height are being used because they are the
+    // only dimensions available to JS that contain non-rounded values. It could
+    // be possible to utilize the getBoundingClientRect if only it's data wasn't
+    // affected by CSS transformations let alone paddings, borders and scroll bars.
+    let width = toFloat(styles.width),
+        height = toFloat(styles.height);
+
+    // Width & height include paddings and borders when the 'border-box' box
+    // model is applied (except for IE).
+    if (styles.boxSizing === 'border-box') {
+        // Following conditions are required to handle Internet Explorer which
+        // doesn't include paddings and borders to computed CSS dimensions.
+        //
+        // We can say that if CSS dimensions + paddings are equal to the "client"
+        // properties then it's either IE, and thus we don't need to subtract
+        // anything, or an element merely doesn't have paddings/borders styles.
+        if (Math.round(width + horizPad) !== clientWidth) {
+            width -= getBordersSize(styles, 'left', 'right') + horizPad;
+        }
+
+        if (Math.round(height + vertPad) !== clientHeight) {
+            height -= getBordersSize(styles, 'top', 'bottom') + vertPad;
+        }
+    }
+
+    // Following steps can't be applied to the document's root element as its
+    // client[Width/Height] properties represent viewport area of the window.
+    // Besides, it's as well not necessary as the <html> itself neither has
+    // rendered scroll bars nor it can be clipped.
+    if (!isDocumentElement(target)) {
+        // In some browsers (only in Firefox, actually) CSS width & height
+        // include scroll bars size which can be removed at this step as scroll
+        // bars are the only difference between rounded dimensions + paddings
+        // and "client" properties, though that is not always true in Chrome.
+        const vertScrollbar = Math.round(width + horizPad) - clientWidth;
+        const horizScrollbar = Math.round(height + vertPad) - clientHeight;
+
+        // Chrome has a rather weird rounding of "client" properties.
+        // E.g. for an element with content width of 314.2px it sometimes gives
+        // the client width of 315px and for the width of 314.7px it may give
+        // 314px. And it doesn't happen all the time. So just ignore this delta
+        // as a non-relevant.
+        if (Math.abs(vertScrollbar) !== 1) {
+            width -= vertScrollbar;
+        }
+
+        if (Math.abs(horizScrollbar) !== 1) {
+            height -= horizScrollbar;
+        }
+    }
+
+    return createRectInit(paddings.left, paddings.top, width, height);
+}
+
+/**
+ * Checks whether provided element is an instance of the SVGGraphicsElement.
+ *
+ * @param {Element} target - Element to be checked.
+ * @returns {boolean}
+ */
+const isSVGGraphicsElement = (() => {
+    // Some browsers, namely IE and Edge, don't have the SVGGraphicsElement
+    // interface.
+    if (typeof SVGGraphicsElement !== 'undefined') {
+        return target => target instanceof getWindowOf(target).SVGGraphicsElement;
+    }
+
+    // If it's so, then check that element is at least an instance of the
+    // SVGElement and that it has the "getBBox" method.
+    // eslint-disable-next-line no-extra-parens
+    return target => (
+        target instanceof getWindowOf(target).SVGElement &&
+        typeof target.getBBox === 'function'
+    );
+})();
+
+/**
+ * Checks whether provided element is a document element (<html>).
+ *
+ * @param {Element} target - Element to be checked.
+ * @returns {boolean}
+ */
+function isDocumentElement(target) {
+    return target === getWindowOf(target).document.documentElement;
+}
+
+/**
+ * Calculates an appropriate content rectangle for provided html or svg element.
+ *
+ * @param {Element} target - Element content rectangle of which needs to be calculated.
+ * @returns {DOMRectInit}
+ */
+export function getContentRect(target) {
+    if (!isBrowser) {
+        return emptyRect;
+    }
+
+    if (isSVGGraphicsElement(target)) {
+        return getSVGContentRect(target);
+    }
+
+    return getHTMLElementContentRect(target);
+}
+
+/**
+ * Creates rectangle with an interface of the DOMRectReadOnly.
+ * Spec: https://drafts.fxtf.org/geometry/#domrectreadonly
+ *
+ * @param {DOMRectInit} rectInit - Object with rectangle's x/y coordinates and dimensions.
+ * @returns {DOMRectReadOnly}
+ */
+export function createReadOnlyRect({x, y, width, height}) {
+    // If DOMRectReadOnly is available use it as a prototype for the rectangle.
+    const Constr = typeof DOMRectReadOnly !== 'undefined' ? DOMRectReadOnly : Object;
+    const rect = Object.create(Constr.prototype);
+
+    // Rectangle's properties are not writable and non-enumerable.
+    defineConfigurable(rect, {
+        x, y, width, height,
+        top: y,
+        right: x + width,
+        bottom: height + y,
+        left: x
+    });
+
+    return rect;
+}
+
+/**
+ * Creates DOMRectInit object based on the provided dimensions and the x/y coordinates.
+ * Spec: https://drafts.fxtf.org/geometry/#dictdef-domrectinit
+ *
+ * @param {number} x - X coordinate.
+ * @param {number} y - Y coordinate.
+ * @param {number} width - Rectangle's width.
+ * @param {number} height - Rectangle's height.
+ * @returns {DOMRectInit}
+ */
+export function createRectInit(x, y, width, height) {
+    return {x, y, width, height};
+}

node_modules/resize-observer-polyfill/src/utils/getWindowOf.js

@@ -0,0 +1,18 @@
+import global from '../shims/global.js';
+
+/**
+ * Returns the global object associated with provided element.
+ *
+ * @param {Object} target
+ * @returns {Object}
+ */
+export default target => {
+    // Assume that the element is an instance of Node, which means that it
+    // has the "ownerDocument" property from which we can retrieve a
+    // corresponding global object.
+    const ownerGlobal = target && target.ownerDocument && target.ownerDocument.defaultView;
+
+    // Return the local global object if it's not possible extract one from
+    // provided element.
+    return ownerGlobal || global;
+};

node_modules/resize-observer-polyfill/src/utils/isBrowser.js

@@ -0,0 +1,4 @@
+/**
+ * Detects whether window and document objects are available in current environment.
+ */
+export default typeof window !== 'undefined' && typeof document !== 'undefined' && window.document === document;

node_modules/resize-observer-polyfill/src/utils/throttle.js

@@ -0,0 +1,78 @@
+import requestAnimationFrame from '../shims/requestAnimationFrame.js';
+
+// Defines minimum timeout before adding a trailing call.
+const trailingTimeout = 2;
+
+/**
+ * Creates a wrapper function which ensures that provided callback will be
+ * invoked only once during the specified delay period.
+ *
+ * @param {Function} callback - Function to be invoked after the delay period.
+ * @param {number} delay - Delay after which to invoke callback.
+ * @returns {Function}
+ */
+export default function (callback, delay) {
+    let leadingCall = false,
+        trailingCall = false,
+        lastCallTime = 0;
+
+    /**
+     * Invokes the original callback function and schedules new invocation if
+     * the "proxy" was called during current request.
+     *
+     * @returns {void}
+     */
+    function resolvePending() {
+        if (leadingCall) {
+            leadingCall = false;
+
+            callback();
+        }
+
+        if (trailingCall) {
+            proxy();
+        }
+    }
+
+    /**
+     * Callback invoked after the specified delay. It will further postpone
+     * invocation of the original function delegating it to the
+     * requestAnimationFrame.
+     *
+     * @returns {void}
+     */
+    function timeoutCallback() {
+        requestAnimationFrame(resolvePending);
+    }
+
+    /**
+     * Schedules invocation of the original function.
+     *
+     * @returns {void}
+     */
+    function proxy() {
+        const timeStamp = Date.now();
+
+        if (leadingCall) {
+            // Reject immediately following calls.
+            if (timeStamp - lastCallTime < trailingTimeout) {
+                return;
+            }
+
+            // Schedule new call to be in invoked when the pending one is resolved.
+            // This is important for "transitions" which never actually start
+            // immediately so there is a chance that we might miss one if change
+            // happens amids the pending invocation.
+            trailingCall = true;
+        } else {
+            leadingCall = true;
+            trailingCall = false;
+
+            setTimeout(timeoutCallback, delay);
+        }
+
+        lastCallTime = timeStamp;
+    }
+
+    return proxy;
+}