/**
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* @license
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* Copyright 2018 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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const defaultOptions = require('./lib/default-options')
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const determineAsValue = require('./lib/determine-as-value')
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const doesChunkBelongToHTML = require('./lib/does-chunk-belong-to-html')
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const extractChunks = require('./lib/extract-chunks')
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class PreloadPlugin {
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constructor (options) {
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this.options = Object.assign({}, defaultOptions, options)
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}
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generateLinks (compilation, htmlPluginData) {
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const options = this.options
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const extractedChunks = extractChunks({
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compilation,
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optionsInclude: options.include
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})
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const htmlChunks = options.include === 'allAssets'
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// Handle all chunks.
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? extractedChunks
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// Only handle chunks imported by this HtmlWebpackPlugin.
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: extractedChunks.filter((chunk) => doesChunkBelongToHTML({
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chunk,
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compilation,
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htmlAssetsChunks: Object.values(htmlPluginData.assets.chunks)
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}))
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// Flatten the list of files.
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const allFiles = htmlChunks.reduce((accumulated, chunk) => {
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return accumulated.concat(chunk.files)
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}, [])
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const uniqueFiles = new Set(allFiles)
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const filteredFiles = [...uniqueFiles].filter(file => {
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return (
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!this.options.fileWhitelist ||
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this.options.fileWhitelist.some(regex => regex.test(file))
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)
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}).filter(file => {
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return (
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!this.options.fileBlacklist ||
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this.options.fileBlacklist.every(regex => !regex.test(file))
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)
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})
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// Sort to ensure the output is predictable.
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const sortedFilteredFiles = filteredFiles.sort()
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const links = []
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const publicPath = compilation.outputOptions.publicPath || ''
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for (const file of sortedFilteredFiles) {
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const href = `${publicPath}${file}`
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const attributes = {
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href,
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rel: options.rel
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}
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// If we're preloading this resource (as opposed to prefetching),
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// then we need to set the 'as' attribute correctly.
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if (options.rel === 'preload') {
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attributes.as = determineAsValue({
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href,
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file,
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optionsAs: options.as
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})
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// On the off chance that we have a cross-origin 'href' attribute,
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// set crossOrigin on the <link> to trigger CORS mode. Non-CORS
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// fonts can't be used.
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if (attributes.as === 'font') {
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attributes.crossorigin = ''
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}
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}
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links.push({
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tagName: 'link',
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attributes
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})
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}
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this.resourceHints = links
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return htmlPluginData
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}
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apply (compiler) {
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const skip = data => {
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const htmlFilename = data.plugin.options.filename
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const exclude = this.options.excludeHtmlNames
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const include = this.options.includeHtmlNames
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return (
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(include && !(include.includes(htmlFilename))) ||
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(exclude && exclude.includes(htmlFilename))
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)
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}
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compiler.hooks.compilation.tap(
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this.constructor.name,
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compilation => {
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compilation.hooks.htmlWebpackPluginBeforeHtmlProcessing.tap(
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this.constructor.name,
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(htmlPluginData) => {
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if (skip(htmlPluginData)) {
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return
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}
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this.generateLinks(compilation, htmlPluginData)
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}
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)
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compilation.hooks.htmlWebpackPluginAlterAssetTags.tap(
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this.constructor.name,
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(htmlPluginData) => {
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if (skip(htmlPluginData)) {
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return
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}
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if (this.resourceHints) {
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htmlPluginData.head = [
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...this.resourceHints,
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...htmlPluginData.head
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]
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}
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return htmlPluginData
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}
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)
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}
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)
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}
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}
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module.exports = PreloadPlugin
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