149 lines
3.5 KiB
JavaScript
149 lines
3.5 KiB
JavaScript
/**
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* @import {Element, Parents} from 'hast'
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*/
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import {whitespace} from 'hast-util-whitespace'
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import {siblingAfter, siblingBefore} from './util/siblings.js'
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import {closing} from './closing.js'
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import {omission} from './omission.js'
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export const opening = omission({
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body,
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colgroup,
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head,
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html,
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tbody
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})
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/**
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* Whether to omit `<html>`.
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*
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* @param {Element} node
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* Element.
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* @returns {boolean}
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* Whether the opening tag can be omitted.
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*/
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function html(node) {
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const head = siblingAfter(node, -1)
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return !head || head.type !== 'comment'
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}
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/**
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* Whether to omit `<head>`.
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*
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* @param {Element} node
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* Element.
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* @returns {boolean}
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* Whether the opening tag can be omitted.
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*/
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function head(node) {
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/** @type {Set<string>} */
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const seen = new Set()
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// Whether `srcdoc` or not,
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// make sure the content model at least doesn’t have too many `base`s/`title`s.
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for (const child of node.children) {
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if (
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child.type === 'element' &&
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(child.tagName === 'base' || child.tagName === 'title')
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) {
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if (seen.has(child.tagName)) return false
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seen.add(child.tagName)
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}
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}
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// “May be omitted if the element is empty,
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// or if the first thing inside the head element is an element.”
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const child = node.children[0]
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return !child || child.type === 'element'
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}
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/**
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* Whether to omit `<body>`.
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*
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* @param {Element} node
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* Element.
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* @returns {boolean}
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* Whether the opening tag can be omitted.
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*/
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function body(node) {
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const head = siblingAfter(node, -1, true)
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return (
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!head ||
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(head.type !== 'comment' &&
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!(head.type === 'text' && whitespace(head.value.charAt(0))) &&
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!(
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head.type === 'element' &&
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(head.tagName === 'meta' ||
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head.tagName === 'link' ||
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head.tagName === 'script' ||
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head.tagName === 'style' ||
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head.tagName === 'template')
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))
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)
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}
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/**
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* Whether to omit `<colgroup>`.
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* The spec describes some logic for the opening tag, but it’s easier to
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* implement in the closing tag, to the same effect, so we handle it there
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* instead.
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*
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* @param {Element} node
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* Element.
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* @param {number | undefined} index
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* Index of element in parent.
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* @param {Parents | undefined} parent
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* Parent of element.
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* @returns {boolean}
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* Whether the opening tag can be omitted.
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*/
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function colgroup(node, index, parent) {
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const previous = siblingBefore(parent, index)
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const head = siblingAfter(node, -1, true)
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// Previous colgroup was already omitted.
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if (
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parent &&
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previous &&
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previous.type === 'element' &&
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previous.tagName === 'colgroup' &&
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closing(previous, parent.children.indexOf(previous), parent)
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) {
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return false
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}
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return Boolean(head && head.type === 'element' && head.tagName === 'col')
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}
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/**
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* Whether to omit `<tbody>`.
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*
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* @param {Element} node
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* Element.
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* @param {number | undefined} index
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* Index of element in parent.
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* @param {Parents | undefined} parent
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* Parent of element.
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* @returns {boolean}
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* Whether the opening tag can be omitted.
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*/
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function tbody(node, index, parent) {
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const previous = siblingBefore(parent, index)
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const head = siblingAfter(node, -1)
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// Previous table section was already omitted.
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if (
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parent &&
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previous &&
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previous.type === 'element' &&
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(previous.tagName === 'thead' || previous.tagName === 'tbody') &&
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closing(previous, parent.children.indexOf(previous), parent)
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) {
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return false
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}
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return Boolean(head && head.type === 'element' && head.tagName === 'tr')
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}
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