Add internationalization support with astro-i18next integration

- Implemented astro-i18next for multi-language support, including English, Dutch, and Italian.
- Configured default locale and language fallback settings.
- Defined routes for localized content in the configuration.
- Updated package.json and package-lock.json to include new dependencies for i18next and related plugins.

node_modules/i18next-http-backend/lib/index.js

@@ -0,0 +1,169 @@
+import { makePromise } from './utils.js'
+import request from './request.js'
+
+const getDefaults = () => {
+  return {
+    loadPath: '/locales/{{lng}}/{{ns}}.json',
+    addPath: '/locales/add/{{lng}}/{{ns}}',
+    parse: data => JSON.parse(data),
+    stringify: JSON.stringify,
+    parsePayload: (namespace, key, fallbackValue) => ({ [key]: fallbackValue || '' }),
+    parseLoadPayload: (languages, namespaces) => undefined,
+    request,
+    reloadInterval: typeof window !== 'undefined' ? false : 60 * 60 * 1000,
+    customHeaders: {},
+    queryStringParams: {},
+    crossDomain: false, // used for XmlHttpRequest
+    withCredentials: false, // used for XmlHttpRequest
+    overrideMimeType: false, // used for XmlHttpRequest
+    requestOptions: { // used for fetch
+      mode: 'cors',
+      credentials: 'same-origin',
+      cache: 'default'
+    }
+  }
+}
+
+class Backend {
+  constructor (services, options = {}, allOptions = {}) {
+    this.services = services
+    this.options = options
+    this.allOptions = allOptions
+    this.type = 'backend'
+    this.init(services, options, allOptions)
+  }
+
+  init (services, options = {}, allOptions = {}) {
+    this.services = services
+    this.options = { ...getDefaults(), ...(this.options || {}), ...options }
+    this.allOptions = allOptions
+    if (this.services && this.options.reloadInterval) {
+      const timer = setInterval(() => this.reload(), this.options.reloadInterval)
+      if (typeof timer === 'object' && typeof timer.unref === 'function') timer.unref()
+    }
+  }
+
+  readMulti (languages, namespaces, callback) {
+    this._readAny(languages, languages, namespaces, namespaces, callback)
+  }
+
+  read (language, namespace, callback) {
+    this._readAny([language], language, [namespace], namespace, callback)
+  }
+
+  _readAny (languages, loadUrlLanguages, namespaces, loadUrlNamespaces, callback) {
+    let loadPath = this.options.loadPath
+    if (typeof this.options.loadPath === 'function') {
+      loadPath = this.options.loadPath(languages, namespaces)
+    }
+
+    loadPath = makePromise(loadPath)
+
+    loadPath.then(resolvedLoadPath => {
+      if (!resolvedLoadPath) return callback(null, {})
+      const url = this.services.interpolator.interpolate(resolvedLoadPath, { lng: languages.join('+'), ns: namespaces.join('+') })
+      this.loadUrl(url, callback, loadUrlLanguages, loadUrlNamespaces)
+    })
+  }
+
+  loadUrl (url, callback, languages, namespaces) {
+    const lng = (typeof languages === 'string') ? [languages] : languages
+    const ns = (typeof namespaces === 'string') ? [namespaces] : namespaces
+    // parseLoadPayload — default undefined
+    const payload = this.options.parseLoadPayload(lng, ns)
+    this.options.request(this.options, url, payload, (err, res) => {
+      if (res && ((res.status >= 500 && res.status < 600) || !res.status)) return callback('failed loading ' + url + '; status code: ' + res.status, true /* retry */)
+      if (res && res.status >= 400 && res.status < 500) return callback('failed loading ' + url + '; status code: ' + res.status, false /* no retry */)
+      if (!res && err && err.message) {
+        const errorMessage = err.message.toLowerCase()
+        // for example:
+        // Chrome: "Failed to fetch"
+        // Firefox: "NetworkError when attempting to fetch resource."
+        // Safari: "Load failed"
+        const isNetworkError = [
+          'failed',
+          'fetch',
+          'network',
+          'load'
+        ].find((term) => errorMessage.indexOf(term) > -1)
+        if (isNetworkError) {
+          return callback('failed loading ' + url + ': ' + err.message, true /* retry */)
+        }
+      }
+      if (err) return callback(err, false)
+
+      let ret, parseErr
+      try {
+        if (typeof res.data === 'string') {
+          ret = this.options.parse(res.data, languages, namespaces)
+        } else { // fallback, which omits calling the parse function
+          ret = res.data
+        }
+      } catch (e) {
+        parseErr = 'failed parsing ' + url + ' to json'
+      }
+      if (parseErr) return callback(parseErr, false)
+      callback(null, ret)
+    })
+  }
+
+  create (languages, namespace, key, fallbackValue, callback) {
+    // If there is a falsey addPath, then abort -- this has been disabled.
+    if (!this.options.addPath) return
+    if (typeof languages === 'string') languages = [languages]
+    const payload = this.options.parsePayload(namespace, key, fallbackValue)
+    let finished = 0
+    const dataArray = []
+    const resArray = []
+    languages.forEach(lng => {
+      let addPath = this.options.addPath
+      if (typeof this.options.addPath === 'function') {
+        addPath = this.options.addPath(lng, namespace)
+      }
+      const url = this.services.interpolator.interpolate(addPath, { lng, ns: namespace })
+
+      this.options.request(this.options, url, payload, (data, res) => {
+        // TODO: if res.status === 4xx do log
+        finished += 1
+        dataArray.push(data)
+        resArray.push(res)
+        if (finished === languages.length) {
+          if (typeof callback === 'function') callback(dataArray, resArray)
+        }
+      })
+    })
+  }
+
+  reload () {
+    const { backendConnector, languageUtils, logger } = this.services
+    const currentLanguage = backendConnector.language
+    if (currentLanguage && currentLanguage.toLowerCase() === 'cimode') return // avoid loading resources for cimode
+
+    const toLoad = []
+    const append = (lng) => {
+      const lngs = languageUtils.toResolveHierarchy(lng)
+      lngs.forEach(l => {
+        if (toLoad.indexOf(l) < 0) toLoad.push(l)
+      })
+    }
+
+    append(currentLanguage)
+
+    if (this.allOptions.preload) this.allOptions.preload.forEach((l) => append(l))
+
+    toLoad.forEach(lng => {
+      this.allOptions.ns.forEach(ns => {
+        backendConnector.read(lng, ns, 'read', null, null, (err, data) => {
+          if (err) logger.warn(`loading namespace ${ns} for language ${lng} failed`, err)
+          if (!err && data) logger.log(`loaded namespace ${ns} for language ${lng}`, data)
+
+          backendConnector.loaded(`${lng}|${ns}`, err, data)
+        })
+      })
+    })
+  }
+}
+
+Backend.type = 'backend'
+
+export default Backend