index.js

/* eslint-disable class-methods-use-this */

import { validate } from 'schema-utils';

import schema from './plugin-options.json';
import { shared, MODULE_TYPE, compareModulesByIdentifier } from './utils';

const pluginName = 'mini-css-extract-plugin';

const REGEXP_CHUNKHASH = /\[chunkhash(?::(\d+))?\]/i;
const REGEXP_CONTENTHASH = /\[contenthash(?::(\d+))?\]/i;
const REGEXP_NAME = /\[name\]/i;
const DEFAULT_FILENAME = '[name].css';

const TYPES = new Set([MODULE_TYPE]);
const CODE_GENERATION_RESULT = {
  sources: new Map(),
  runtimeRequirements: new Set(),
};

class MiniCssExtractPlugin {
  static getCssModule(webpack) {
    class CssModule extends webpack.Module {
      constructor({
        context,
        identifier,
        identifierIndex,
        content,
        media,
        sourceMap,
        assets,
        assetsInfo,
      }) {
        super(MODULE_TYPE, context);

        this.id = '';
        this._context = context;
        this._identifier = identifier;
        this._identifierIndex = identifierIndex;
        this.content = content;
        this.media = media;
        this.sourceMap = sourceMap;
        this.buildInfo = {
          assets,
          assetsInfo,
        };
        this.buildMeta = {};
      }

      // no source() so webpack 4 doesn't do add stuff to the bundle

      size() {
        return this.content.length;
      }

      identifier() {
        return `css|${this._identifier}|${this._identifierIndex}`;
      }

      readableIdentifier(requestShortener) {
        return `css ${requestShortener.shorten(this._identifier)}${
          this._identifierIndex ? ` (${this._identifierIndex})` : ''
        }`;
      }

      // eslint-disable-next-line class-methods-use-this
      getSourceTypes() {
        return TYPES;
      }

      // eslint-disable-next-line class-methods-use-this
      codeGeneration() {
        return CODE_GENERATION_RESULT;
      }

      nameForCondition() {
        const resource = this._identifier.split('!').pop();
        const idx = resource.indexOf('?');

        if (idx >= 0) {
          return resource.substring(0, idx);
        }

        return resource;
      }

      updateCacheModule(module) {
        this.content = module.content;
        this.media = module.media;
        this.sourceMap = module.sourceMap;
      }

      // eslint-disable-next-line class-methods-use-this
      needRebuild() {
        return true;
      }

      // eslint-disable-next-line class-methods-use-this
      needBuild(context, callback) {
        callback(null, false);
      }

      build(options, compilation, resolver, fileSystem, callback) {
        this.buildInfo = {};
        this.buildMeta = {};

        callback();
      }

      updateHash(hash, context) {
        super.updateHash(hash, context);

        hash.update(this.content);
        hash.update(this.media || '');
        hash.update(this.sourceMap ? JSON.stringify(this.sourceMap) : '');
      }

      serialize(context) {
        const { write } = context;

        write(this._context);
        write(this._identifier);
        write(this._identifierIndex);
        write(this.content);
        write(this.media);
        write(this.sourceMap);
        write(this.buildInfo);

        super.serialize(context);
      }

      deserialize(context) {
        super.deserialize(context);
      }
    }

    if (
      webpack.util &&
      webpack.util.serialization &&
      webpack.util.serialization.register
    ) {
      webpack.util.serialization.register(
        CssModule,
        'mini-css-extract-plugin/dist/CssModule',
        null,
        {
          serialize(instance, context) {
            instance.serialize(context);
          },
          deserialize(context) {
            const { read } = context;

            const contextModule = read();
            const identifier = read();
            const identifierIndex = read();
            const content = read();
            const media = read();
            const sourceMap = read();
            const { assets, assetsInfo } = read();

            const dep = new CssModule({
              context: contextModule,
              identifier,
              identifierIndex,
              content,
              media,
              sourceMap,
              assets,
              assetsInfo,
            });

            dep.deserialize(context);

            return dep;
          },
        }
      );
    }

    return CssModule;
  }

  static getCssDependency(webpack) {
    // eslint-disable-next-line no-shadow
    class CssDependency extends webpack.Dependency {
      constructor(
        { identifier, content, media, sourceMap },
        context,
        identifierIndex
      ) {
        super();

        this.identifier = identifier;
        this.identifierIndex = identifierIndex;
        this.content = content;
        this.media = media;
        this.sourceMap = sourceMap;
        this.context = context;
        // eslint-disable-next-line no-undefined
        this.assets = undefined;
        // eslint-disable-next-line no-undefined
        this.assetsInfo = undefined;
      }

      getResourceIdentifier() {
        return `css-module-${this.identifier}-${this.identifierIndex}`;
      }

      // eslint-disable-next-line class-methods-use-this
      getModuleEvaluationSideEffectsState() {
        return webpack.ModuleGraphConnection.TRANSITIVE_ONLY;
      }

      serialize(context) {
        const { write } = context;

        write(this.identifier);
        write(this.content);
        write(this.media);
        write(this.sourceMap);
        write(this.context);
        write(this.identifierIndex);
        write(this.assets);
        write(this.assetsInfo);

        super.serialize(context);
      }

      deserialize(context) {
        super.deserialize(context);
      }
    }

    if (
      webpack.util &&
      webpack.util.serialization &&
      webpack.util.serialization.register
    ) {
      webpack.util.serialization.register(
        CssDependency,
        'mini-css-extract-plugin/dist/CssDependency',
        null,
        {
          serialize(instance, context) {
            instance.serialize(context);
          },
          deserialize(context) {
            const { read } = context;
            const dep = new CssDependency(
              {
                identifier: read(),
                content: read(),
                media: read(),
                sourceMap: read(),
              },
              read(),
              read()
            );

            const assets = read();
            const assetsInfo = read();

            dep.assets = assets;
            dep.assetsInfo = assetsInfo;

            dep.deserialize(context);

            return dep;
          },
        }
      );
    }

    return CssDependency;
  }

  constructor(options = {}) {
    validate(schema, options, {
      name: 'Mini CSS Extract Plugin',
      baseDataPath: 'options',
    });

    this._sortedModulesCache = new WeakMap();

    this.options = Object.assign(
      { filename: DEFAULT_FILENAME, ignoreOrder: false },
      options
    );

    this.runtimeOptions = {
      insert: options.insert,
      linkType:
        // Todo in next major release set default to "false"
        options.linkType === true || typeof options.linkType === 'undefined'
          ? 'text/css'
          : options.linkType,
      attributes: options.attributes,
    };

    if (!this.options.chunkFilename) {
      const { filename } = this.options;

      if (typeof filename !== 'function') {
        const hasName = filename.includes('[name]');
        const hasId = filename.includes('[id]');
        const hasChunkHash = filename.includes('[chunkhash]');
        const hasContentHash = filename.includes('[contenthash]');

        // Anything changing depending on chunk is fine
        if (hasChunkHash || hasContentHash || hasName || hasId) {
          this.options.chunkFilename = filename;
        } else {
          // Otherwise prefix "[id]." in front of the basename to make it changing
          this.options.chunkFilename = filename.replace(
            /(^|\/)([^/]*(?:\?|$))/,
            '$1[id].$2'
          );
        }
      } else {
        this.options.chunkFilename = '[id].css';
      }
    }
  }

  /** @param {import("webpack").Compiler} compiler */
  apply(compiler) {
    const webpack = compiler.webpack
      ? compiler.webpack
      : // eslint-disable-next-line global-require
        require('webpack');

    // TODO bug in webpack, remove it after it will be fixed
    // webpack tries to `require` loader firstly when serializer doesn't found
    if (
      webpack.util &&
      webpack.util.serialization &&
      webpack.util.serialization.registerLoader
    ) {
      webpack.util.serialization.registerLoader(
        /^mini-css-extract-plugin\//,
        () => true
      );
    }

    const isWebpack4 = compiler.webpack
      ? false
      : typeof compiler.resolvers !== 'undefined';

    if (!isWebpack4) {
      const { splitChunks } = compiler.options.optimization;

      if (splitChunks) {
        if (splitChunks.defaultSizeTypes.includes('...')) {
          splitChunks.defaultSizeTypes.push(MODULE_TYPE);
        }
      }
    }

    // initializeCssDependency
    // eslint-disable-next-line no-shadow
    const { CssModule, CssDependency } = shared(webpack, (webpack) => {
      // eslint-disable-next-line no-shadow
      const CssModule = MiniCssExtractPlugin.getCssModule(webpack);
      // eslint-disable-next-line no-shadow
      const CssDependency = MiniCssExtractPlugin.getCssDependency(webpack);

      return { CssModule, CssDependency };
    });

    compiler.hooks.thisCompilation.tap(pluginName, (compilation) => {
      class CssModuleFactory {
        // eslint-disable-next-line class-methods-use-this
        create({ dependencies: [dependency] }, callback) {
          callback(null, new CssModule(dependency));
        }
      }

      compilation.dependencyFactories.set(
        CssDependency,
        new CssModuleFactory()
      );

      class CssDependencyTemplate {
        // eslint-disable-next-line class-methods-use-this
        apply() {}
      }

      compilation.dependencyTemplates.set(
        CssDependency,
        new CssDependencyTemplate()
      );

      if (isWebpack4) {
        compilation.mainTemplate.hooks.renderManifest.tap(
          pluginName,
          (result, { chunk }) => {
            const { chunkGraph } = compilation;

            const renderedModules = Array.from(
              this.getChunkModules(chunk, chunkGraph)
            ).filter((module) => module.type === MODULE_TYPE);

            const filenameTemplate =
              chunk.filenameTemplate || this.options.filename;

            if (renderedModules.length > 0) {
              result.push({
                render: () =>
                  this.renderContentAsset(
                    compiler,
                    compilation,
                    chunk,
                    renderedModules,
                    compilation.runtimeTemplate.requestShortener
                  ),
                filenameTemplate,
                pathOptions: {
                  chunk,
                  contentHashType: MODULE_TYPE,
                },
                identifier: `${pluginName}.${chunk.id}`,
                hash: chunk.contentHash[MODULE_TYPE],
              });
            }
          }
        );

        compilation.chunkTemplate.hooks.renderManifest.tap(
          pluginName,
          (result, { chunk }) => {
            const { chunkGraph } = compilation;

            const renderedModules = Array.from(
              this.getChunkModules(chunk, chunkGraph)
            ).filter((module) => module.type === MODULE_TYPE);

            const filenameTemplate =
              chunk.filenameTemplate || this.options.chunkFilename;

            if (renderedModules.length > 0) {
              result.push({
                render: () =>
                  this.renderContentAsset(
                    compiler,
                    compilation,
                    chunk,
                    renderedModules,
                    compilation.runtimeTemplate.requestShortener
                  ),
                filenameTemplate,
                pathOptions: {
                  chunk,
                  contentHashType: MODULE_TYPE,
                },
                identifier: `${pluginName}.${chunk.id}`,
                hash: chunk.contentHash[MODULE_TYPE],
              });
            }
          }
        );
      } else {
        compilation.hooks.renderManifest.tap(
          pluginName,
          (result, { chunk }) => {
            const { chunkGraph } = compilation;
            const { HotUpdateChunk } = webpack;

            // We don't need hot update chunks for css
            // We will use the real asset instead to update
            if (chunk instanceof HotUpdateChunk) {
              return;
            }

            const renderedModules = Array.from(
              this.getChunkModules(chunk, chunkGraph)
            ).filter((module) => module.type === MODULE_TYPE);

            const filenameTemplate = chunk.canBeInitial()
              ? this.options.filename
              : this.options.chunkFilename;

            if (renderedModules.length > 0) {
              result.push({
                render: () =>
                  this.renderContentAsset(
                    compiler,
                    compilation,
                    chunk,
                    renderedModules,
                    compilation.runtimeTemplate.requestShortener
                  ),
                filenameTemplate,
                pathOptions: {
                  chunk,
                  contentHashType: MODULE_TYPE,
                },
                identifier: `${pluginName}.${chunk.id}`,
                hash: chunk.contentHash[MODULE_TYPE],
              });
            }
          }
        );
      }

      /*
       * For webpack 5 this will be unneeded once the logic uses a RuntimeModule
       * as the content of runtime modules is hashed and added to the chunk hash automatically
       * */
      if (isWebpack4) {
        compilation.mainTemplate.hooks.hashForChunk.tap(
          pluginName,
          (hash, chunk) => {
            const { chunkFilename } = this.options;

            if (REGEXP_CHUNKHASH.test(chunkFilename)) {
              hash.update(JSON.stringify(chunk.getChunkMaps(true).hash));
            }

            if (REGEXP_CONTENTHASH.test(chunkFilename)) {
              hash.update(
                JSON.stringify(
                  chunk.getChunkMaps(true).contentHash[MODULE_TYPE] || {}
                )
              );
            }

            if (REGEXP_NAME.test(chunkFilename)) {
              hash.update(JSON.stringify(chunk.getChunkMaps(true).name));
            }
          }
        );
      }

      compilation.hooks.contentHash.tap(pluginName, (chunk) => {
        const { outputOptions, chunkGraph } = compilation;
        const modules = isWebpack4
          ? Array.from(this.getChunkModules(chunk, chunkGraph)).filter(
              (module) => module.type === MODULE_TYPE
            )
          : this.sortModules(
              compilation,
              chunk,
              chunkGraph.getChunkModulesIterableBySourceType(
                chunk,
                MODULE_TYPE
              ),
              compilation.runtimeTemplate.requestShortener
            );

        if (modules) {
          const { hashFunction, hashDigest, hashDigestLength } = outputOptions;
          const createHash = compiler.webpack
            ? compiler.webpack.util.createHash
            : webpack.util.createHash;
          const hash = createHash(hashFunction);

          for (const m of modules) {
            m.updateHash(hash, { chunkGraph });
          }

          // eslint-disable-next-line no-param-reassign
          chunk.contentHash[MODULE_TYPE] = hash
            .digest(hashDigest)
            .substring(0, hashDigestLength);
        }
      });

      const { Template } = webpack;
      const { mainTemplate } = compilation;

      if (isWebpack4) {
        mainTemplate.hooks.localVars.tap(pluginName, (source, chunk) => {
          const chunkMap = this.getCssChunkObject(chunk, compilation);

          if (Object.keys(chunkMap).length > 0) {
            return Template.asString([
              source,
              '',
              '// object to store loaded CSS chunks',
              'var installedCssChunks = {',
              Template.indent(
                chunk.ids.map((id) => `${JSON.stringify(id)}: 0`).join(',\n')
              ),
              '};',
            ]);
          }

          return source;
        });

        mainTemplate.hooks.requireEnsure.tap(
          pluginName,
          (source, chunk, hash) => {
            const chunkMap = this.getCssChunkObject(chunk, compilation);

            if (Object.keys(chunkMap).length > 0) {
              const chunkMaps = chunk.getChunkMaps();
              const { crossOriginLoading } = mainTemplate.outputOptions;
              const linkHrefPath = mainTemplate.getAssetPath(
                JSON.stringify(this.options.chunkFilename),
                {
                  hash: `" + ${mainTemplate.renderCurrentHashCode(hash)} + "`,
                  hashWithLength: (length) =>
                    `" + ${mainTemplate.renderCurrentHashCode(
                      hash,
                      length
                    )} + "`,
                  chunk: {
                    id: '" + chunkId + "',
                    hash: `" + ${JSON.stringify(chunkMaps.hash)}[chunkId] + "`,
                    hashWithLength(length) {
                      const shortChunkHashMap = Object.create(null);

                      for (const chunkId of Object.keys(chunkMaps.hash)) {
                        if (typeof chunkMaps.hash[chunkId] === 'string') {
                          shortChunkHashMap[chunkId] = chunkMaps.hash[
                            chunkId
                          ].substring(0, length);
                        }
                      }

                      return `" + ${JSON.stringify(
                        shortChunkHashMap
                      )}[chunkId] + "`;
                    },
                    contentHash: {
                      [MODULE_TYPE]: `" + ${JSON.stringify(
                        chunkMaps.contentHash[MODULE_TYPE]
                      )}[chunkId] + "`,
                    },
                    contentHashWithLength: {
                      [MODULE_TYPE]: (length) => {
                        const shortContentHashMap = {};
                        const contentHash = chunkMaps.contentHash[MODULE_TYPE];

                        for (const chunkId of Object.keys(contentHash)) {
                          if (typeof contentHash[chunkId] === 'string') {
                            shortContentHashMap[chunkId] = contentHash[
                              chunkId
                            ].substring(0, length);
                          }
                        }

                        return `" + ${JSON.stringify(
                          shortContentHashMap
                        )}[chunkId] + "`;
                      },
                    },
                    name: `" + (${JSON.stringify(
                      chunkMaps.name
                    )}[chunkId]||chunkId) + "`,
                  },
                  contentHashType: MODULE_TYPE,
                }
              );

              return Template.asString([
                source,
                '',
                `// ${pluginName} CSS loading`,
                `var cssChunks = ${JSON.stringify(chunkMap)};`,
                'if(installedCssChunks[chunkId]) promises.push(installedCssChunks[chunkId]);',
                'else if(installedCssChunks[chunkId] !== 0 && cssChunks[chunkId]) {',
                Template.indent([
                  'promises.push(installedCssChunks[chunkId] = new Promise(function(resolve, reject) {',
                  Template.indent([
                    `var href = ${linkHrefPath};`,
                    `var fullhref = ${mainTemplate.requireFn}.p + href;`,
                    'var existingLinkTags = document.getElementsByTagName("link");',
                    'for(var i = 0; i < existingLinkTags.length; i++) {',
                    Template.indent([
                      'var tag = existingLinkTags[i];',
                      'var dataHref = tag.getAttribute("data-href") || tag.getAttribute("href");',
                      'if(tag.rel === "stylesheet" && (dataHref === href || dataHref === fullhref)) return resolve();',
                    ]),
                    '}',
                    'var existingStyleTags = document.getElementsByTagName("style");',
                    'for(var i = 0; i < existingStyleTags.length; i++) {',
                    Template.indent([
                      'var tag = existingStyleTags[i];',
                      'var dataHref = tag.getAttribute("data-href");',
                      'if(dataHref === href || dataHref === fullhref) return resolve();',
                    ]),
                    '}',
                    'var linkTag = document.createElement("link");',
                    this.runtimeOptions.attributes
                      ? Template.asString(
                          Object.entries(this.runtimeOptions.attributes).map(
                            (entry) => {
                              const [key, value] = entry;

                              return `linkTag.setAttribute(${JSON.stringify(
                                key
                              )}, ${JSON.stringify(value)});`;
                            }
                          )
                        )
                      : '',
                    'linkTag.rel = "stylesheet";',
                    this.runtimeOptions.linkType
                      ? `linkTag.type = ${JSON.stringify(
                          this.runtimeOptions.linkType
                        )};`
                      : '',
                    'var onLinkComplete = function (event) {',
                    Template.indent([
                      '// avoid mem leaks.',
                      'linkTag.onerror = linkTag.onload = null;',
                      "if (event.type === 'load') {",
                      Template.indent(['resolve();']),
                      '} else {',
                      Template.indent([
                        "var errorType = event && (event.type === 'load' ? 'missing' : event.type);",
                        'var realHref = event && event.target && event.target.href || fullhref;',
                        'var err = new Error("Loading CSS chunk " + chunkId + " failed.\\n(" + realHref + ")");',
                        'err.code = "CSS_CHUNK_LOAD_FAILED";',
                        'err.type = errorType;',
                        'err.request = realHref;',
                        'delete installedCssChunks[chunkId]',
                        'linkTag.parentNode.removeChild(linkTag)',
                        'reject(err);',
                      ]),
                      '}',
                    ]),
                    '};',
                    'linkTag.onerror = linkTag.onload = onLinkComplete;',
                    'linkTag.href = fullhref;',
                    crossOriginLoading
                      ? Template.asString([
                          `if (linkTag.href.indexOf(window.location.origin + '/') !== 0) {`,
                          Template.indent(
                            `linkTag.crossOrigin = ${JSON.stringify(
                              crossOriginLoading
                            )};`
                          ),
                          '}',
                        ])
                      : '',
                    typeof this.runtimeOptions.insert !== 'undefined'
                      ? typeof this.runtimeOptions.insert === 'function'
                        ? `(${this.runtimeOptions.insert.toString()})(linkTag)`
                        : Template.asString([
                            `var target = document.querySelector("${this.runtimeOptions.insert}");`,
                            `target.parentNode.insertBefore(linkTag, target.nextSibling);`,
                          ])
                      : Template.asString([
                          'document.head.appendChild(linkTag);',
                        ]),
                  ]),
                  '}).then(function() {',
                  Template.indent(['installedCssChunks[chunkId] = 0;']),
                  '}));',
                ]),
                '}',
              ]);
            }

            return source;
          }
        );
      } else {
        const { RuntimeGlobals, runtime } = webpack;

        // eslint-disable-next-line no-shadow
        const getCssChunkObject = (mainChunk, compilation) => {
          const obj = {};
          const { chunkGraph } = compilation;

          for (const chunk of mainChunk.getAllAsyncChunks()) {
            const modules = chunkGraph.getOrderedChunkModulesIterable(
              chunk,
              compareModulesByIdentifier
            );
            for (const module of modules) {
              if (module.type === MODULE_TYPE) {
                obj[chunk.id] = 1;
                break;
              }
            }
          }

          return obj;
        };

        const { RuntimeModule } = webpack;

        class CssLoadingRuntimeModule extends RuntimeModule {
          constructor(runtimeRequirements, runtimeOptions) {
            super('css loading', 10);

            this.runtimeRequirements = runtimeRequirements;
            this.runtimeOptions = runtimeOptions;
          }

          generate() {
            const { chunk, runtimeRequirements } = this;
            const {
              runtimeTemplate,
              outputOptions: { crossOriginLoading },
            } = this.compilation;
            const chunkMap = getCssChunkObject(chunk, this.compilation);

            const withLoading =
              runtimeRequirements.has(RuntimeGlobals.ensureChunkHandlers) &&
              Object.keys(chunkMap).length > 0;
            const withHmr = runtimeRequirements.has(
              RuntimeGlobals.hmrDownloadUpdateHandlers
            );

            if (!withLoading && !withHmr) {
              return null;
            }

            return Template.asString([
              `var createStylesheet = ${runtimeTemplate.basicFunction(
                'chunkId, fullhref, resolve, reject',
                [
                  'var linkTag = document.createElement("link");',
                  this.runtimeOptions.attributes
                    ? Template.asString(
                        Object.entries(this.runtimeOptions.attributes).map(
                          (entry) => {
                            const [key, value] = entry;

                            return `linkTag.setAttribute(${JSON.stringify(
                              key
                            )}, ${JSON.stringify(value)});`;
                          }
                        )
                      )
                    : '',
                  'linkTag.rel = "stylesheet";',
                  this.runtimeOptions.linkType
                    ? `linkTag.type = ${JSON.stringify(
                        this.runtimeOptions.linkType
                      )};`
                    : '',
                  `var onLinkComplete = ${runtimeTemplate.basicFunction(
                    'event',
                    [
                      '// avoid mem leaks.',
                      'linkTag.onerror = linkTag.onload = null;',
                      "if (event.type === 'load') {",
                      Template.indent(['resolve();']),
                      '} else {',
                      Template.indent([
                        "var errorType = event && (event.type === 'load' ? 'missing' : event.type);",
                        'var realHref = event && event.target && event.target.href || fullhref;',
                        'var err = new Error("Loading CSS chunk " + chunkId + " failed.\\n(" + realHref + ")");',
                        'err.code = "CSS_CHUNK_LOAD_FAILED";',
                        'err.type = errorType;',
                        'err.request = realHref;',
                        'linkTag.parentNode.removeChild(linkTag)',
                        'reject(err);',
                      ]),
                      '}',
                    ]
                  )}`,
                  'linkTag.onerror = linkTag.onload = onLinkComplete;',
                  'linkTag.href = fullhref;',
                  crossOriginLoading
                    ? Template.asString([
                        `if (linkTag.href.indexOf(window.location.origin + '/') !== 0) {`,
                        Template.indent(
                          `linkTag.crossOrigin = ${JSON.stringify(
                            crossOriginLoading
                          )};`
                        ),
                        '}',
                      ])
                    : '',
                  typeof this.runtimeOptions.insert !== 'undefined'
                    ? typeof this.runtimeOptions.insert === 'function'
                      ? `(${this.runtimeOptions.insert.toString()})(linkTag)`
                      : Template.asString([
                          `var target = document.querySelector("${this.runtimeOptions.insert}");`,
                          `target.parentNode.insertBefore(linkTag, target.nextSibling);`,
                        ])
                    : Template.asString([
                        'document.head.appendChild(linkTag);',
                      ]),
                  'return linkTag;',
                ]
              )};`,
              `var findStylesheet = ${runtimeTemplate.basicFunction(
                'href, fullhref',
                [
                  'var existingLinkTags = document.getElementsByTagName("link");',
                  'for(var i = 0; i < existingLinkTags.length; i++) {',
                  Template.indent([
                    'var tag = existingLinkTags[i];',
                    'var dataHref = tag.getAttribute("data-href") || tag.getAttribute("href");',
                    'if(tag.rel === "stylesheet" && (dataHref === href || dataHref === fullhref)) return tag;',
                  ]),
                  '}',
                  'var existingStyleTags = document.getElementsByTagName("style");',
                  'for(var i = 0; i < existingStyleTags.length; i++) {',
                  Template.indent([
                    'var tag = existingStyleTags[i];',
                    'var dataHref = tag.getAttribute("data-href");',
                    'if(dataHref === href || dataHref === fullhref) return tag;',
                  ]),
                  '}',
                ]
              )};`,
              `var loadStylesheet = ${runtimeTemplate.basicFunction(
                'chunkId',
                `return new Promise(${runtimeTemplate.basicFunction(
                  'resolve, reject',
                  [
                    `var href = ${RuntimeGlobals.require}.miniCssF(chunkId);`,
                    `var fullhref = ${RuntimeGlobals.publicPath} + href;`,
                    'if(findStylesheet(href, fullhref)) return resolve();',
                    'createStylesheet(chunkId, fullhref, resolve, reject);',
                  ]
                )});`
              )}`,
              withLoading
                ? Template.asString([
                    '// object to store loaded CSS chunks',
                    'var installedCssChunks = {',
                    Template.indent(
                      chunk.ids
                        .map((id) => `${JSON.stringify(id)}: 0`)
                        .join(',\n')
                    ),
                    '};',
                    '',
                    `${
                      RuntimeGlobals.ensureChunkHandlers
                    }.miniCss = ${runtimeTemplate.basicFunction(
                      'chunkId, promises',
                      [
                        `var cssChunks = ${JSON.stringify(chunkMap)};`,
                        'if(installedCssChunks[chunkId]) promises.push(installedCssChunks[chunkId]);',
                        'else if(installedCssChunks[chunkId] !== 0 && cssChunks[chunkId]) {',
                        Template.indent([
                          `promises.push(installedCssChunks[chunkId] = loadStylesheet(chunkId).then(${runtimeTemplate.basicFunction(
                            '',
                            'installedCssChunks[chunkId] = 0;'
                          )}, ${runtimeTemplate.basicFunction('e', [
                            'delete installedCssChunks[chunkId];',
                            'throw e;',
                          ])}));`,
                        ]),
                        '}',
                      ]
                    )};`,
                  ])
                : '// no chunk loading',
              '',
              withHmr
                ? Template.asString([
                    'var oldTags = [];',
                    'var newTags = [];',
                    `var applyHandler = ${runtimeTemplate.basicFunction(
                      'options',
                      [
                        `return { dispose: ${runtimeTemplate.basicFunction('', [
                          'for(var i = 0; i < oldTags.length; i++) {',
                          Template.indent([
                            'var oldTag = oldTags[i];',
                            'if(oldTag.parentNode) oldTag.parentNode.removeChild(oldTag);',
                          ]),
                          '}',
                          'oldTags.length = 0;',
                        ])}, apply: ${runtimeTemplate.basicFunction('', [
                          'for(var i = 0; i < newTags.length; i++) newTags[i].rel = "stylesheet";',
                          'newTags.length = 0;',
                        ])} };`,
                      ]
                    )}`,
                    `${
                      RuntimeGlobals.hmrDownloadUpdateHandlers
                    }.miniCss = ${runtimeTemplate.basicFunction(
                      'chunkIds, removedChunks, removedModules, promises, applyHandlers, updatedModulesList',
                      [
                        'applyHandlers.push(applyHandler);',
                        `chunkIds.forEach(${runtimeTemplate.basicFunction(
                          'chunkId',
                          [
                            `var href = ${RuntimeGlobals.require}.miniCssF(chunkId);`,
                            `var fullhref = ${RuntimeGlobals.publicPath} + href;`,
                            'const oldTag = findStylesheet(href, fullhref);',
                            'if(!oldTag) return;',
                            `promises.push(new Promise(${runtimeTemplate.basicFunction(
                              'resolve, reject',
                              [
                                `var tag = createStylesheet(chunkId, fullhref, ${runtimeTemplate.basicFunction(
                                  '',
                                  [
                                    'tag.as = "style";',
                                    'tag.rel = "preload";',
                                    'resolve();',
                                  ]
                                )}, reject);`,
                                'oldTags.push(oldTag);',
                                'newTags.push(tag);',
                              ]
                            )}));`,
                          ]
                        )});`,
                      ]
                    )}`,
                  ])
                : '// no hmr',
            ]);
          }
        }

        const enabledChunks = new WeakSet();

        const handler = (chunk, set) => {
          if (enabledChunks.has(chunk)) {
            return;
          }

          enabledChunks.add(chunk);

          if (
            typeof this.options.chunkFilename === 'string' &&
            /\[(full)?hash(:\d+)?\]/.test(this.options.chunkFilename)
          ) {
            set.add(RuntimeGlobals.getFullHash);
          }

          set.add(RuntimeGlobals.publicPath);

          compilation.addRuntimeModule(
            chunk,
            new runtime.GetChunkFilenameRuntimeModule(
              MODULE_TYPE,
              'mini-css',
              `${RuntimeGlobals.require}.miniCssF`,
              (referencedChunk) => {
                if (!referencedChunk.contentHash[MODULE_TYPE]) {
                  return false;
                }

                return referencedChunk.canBeInitial()
                  ? this.options.filename
                  : this.options.chunkFilename;
              },
              true
            )
          );

          compilation.addRuntimeModule(
            chunk,
            new CssLoadingRuntimeModule(set, this.runtimeOptions)
          );
        };

        compilation.hooks.runtimeRequirementInTree
          .for(RuntimeGlobals.ensureChunkHandlers)
          .tap(pluginName, handler);
        compilation.hooks.runtimeRequirementInTree
          .for(RuntimeGlobals.hmrDownloadUpdateHandlers)
          .tap(pluginName, handler);
      }
    });
  }

  getChunkModules(chunk, chunkGraph) {
    return typeof chunkGraph !== 'undefined'
      ? chunkGraph.getOrderedChunkModulesIterable(
          chunk,
          compareModulesByIdentifier
        )
      : chunk.modulesIterable;
  }

  getCssChunkObject(mainChunk, compilation) {
    const obj = {};
    const { chunkGraph } = compilation;

    for (const chunk of mainChunk.getAllAsyncChunks()) {
      for (const module of this.getChunkModules(chunk, chunkGraph)) {
        if (module.type === MODULE_TYPE) {
          obj[chunk.id] = 1;
          break;
        }
      }
    }

    return obj;
  }

  sortModules(compilation, chunk, modules, requestShortener) {
    let usedModules = this._sortedModulesCache.get(chunk);

    if (usedModules || !modules) {
      return usedModules;
    }

    modules = [...modules];

    const [chunkGroup] = chunk.groupsIterable;
    const moduleIndexFunctionName =
      typeof compilation.chunkGraph !== 'undefined'
        ? 'getModulePostOrderIndex'
        : 'getModuleIndex2';

    if (typeof chunkGroup[moduleIndexFunctionName] === 'function') {
      // Store dependencies for modules
      const moduleDependencies = new Map(modules.map((m) => [m, new Set()]));
      const moduleDependenciesReasons = new Map(
        modules.map((m) => [m, new Map()])
      );

      // Get ordered list of modules per chunk group
      // This loop also gathers dependencies from the ordered lists
      // Lists are in reverse order to allow to use Array.pop()
      const modulesByChunkGroup = Array.from(chunk.groupsIterable, (cg) => {
        const sortedModules = modules
          .map((m) => {
            return {
              module: m,
              index: cg[moduleIndexFunctionName](m),
            };
          })
          // eslint-disable-next-line no-undefined
          .filter((item) => item.index !== undefined)
          .sort((a, b) => b.index - a.index)
          .map((item) => item.module);

        for (let i = 0; i < sortedModules.length; i++) {
          const set = moduleDependencies.get(sortedModules[i]);
          const reasons = moduleDependenciesReasons.get(sortedModules[i]);

          for (let j = i + 1; j < sortedModules.length; j++) {
            const module = sortedModules[j];
            set.add(module);
            const reason = reasons.get(module) || new Set();
            reason.add(cg);
            reasons.set(module, reason);
          }
        }

        return sortedModules;
      });

      // set with already included modules in correct order
      usedModules = new Set();

      const unusedModulesFilter = (m) => !usedModules.has(m);

      while (usedModules.size < modules.length) {
        let success = false;
        let bestMatch;
        let bestMatchDeps;

        // get first module where dependencies are fulfilled
        for (const list of modulesByChunkGroup) {
          // skip and remove already added modules
          while (list.length > 0 && usedModules.has(list[list.length - 1])) {
            list.pop();
          }

          // skip empty lists
          if (list.length !== 0) {
            const module = list[list.length - 1];
            const deps = moduleDependencies.get(module);
            // determine dependencies that are not yet included
            const failedDeps = Array.from(deps).filter(unusedModulesFilter);

            // store best match for fallback behavior
            if (!bestMatchDeps || bestMatchDeps.length > failedDeps.length) {
              bestMatch = list;
              bestMatchDeps = failedDeps;
            }

            if (failedDeps.length === 0) {
              // use this module and remove it from list
              usedModules.add(list.pop());
              success = true;
              break;
            }
          }
        }

        if (!success) {
          // no module found => there is a conflict
          // use list with fewest failed deps
          // and emit a warning
          const fallbackModule = bestMatch.pop();

          if (!this.options.ignoreOrder) {
            const reasons = moduleDependenciesReasons.get(fallbackModule);
            compilation.warnings.push(
              new Error(
                [
                  `chunk ${chunk.name || chunk.id} [${pluginName}]`,
                  'Conflicting order. Following module has been added:',
                  ` * ${fallbackModule.readableIdentifier(requestShortener)}`,
                  'despite it was not able to fulfill desired ordering with these modules:',
                  ...bestMatchDeps.map((m) => {
                    const goodReasonsMap = moduleDependenciesReasons.get(m);
                    const goodReasons =
                      goodReasonsMap && goodReasonsMap.get(fallbackModule);
                    const failedChunkGroups = Array.from(
                      reasons.get(m),
                      (cg) => cg.name
                    ).join(', ');
                    const goodChunkGroups =
                      goodReasons &&
                      Array.from(goodReasons, (cg) => cg.name).join(', ');
                    return [
                      ` * ${m.readableIdentifier(requestShortener)}`,
                      `   - couldn't fulfill desired order of chunk group(s) ${failedChunkGroups}`,
                      goodChunkGroups &&
                        `   - while fulfilling desired order of chunk group(s) ${goodChunkGroups}`,
                    ]
                      .filter(Boolean)
                      .join('\n');
                  }),
                ].join('\n')
              )
            );
          }

          usedModules.add(fallbackModule);
        }
      }
    } else {
      // fallback for older webpack versions
      // (to avoid a breaking change)
      // TODO remove this in next major version
      // and increase minimum webpack version to 4.12.0
      modules.sort((a, b) => a.index2 - b.index2);
      usedModules = modules;
    }

    this._sortedModulesCache.set(chunk, usedModules);

    return usedModules;
  }

  renderContentAsset(compiler, compilation, chunk, modules, requestShortener) {
    const usedModules = this.sortModules(
      compilation,
      chunk,
      modules,
      requestShortener
    );

    // TODO remove after drop webpack v4
    const { ConcatSource, SourceMapSource, RawSource } = compiler.webpack
      ? compiler.webpack.sources
      : // eslint-disable-next-line global-require
        require('webpack-sources');

    const source = new ConcatSource();
    const externalsSource = new ConcatSource();

    for (const m of usedModules) {
      let content = m.content.toString();

      if (/^@import url/.test(content)) {
        // HACK for IE
        // http://stackoverflow.com/a/14676665/1458162
        if (m.media) {
          // insert media into the @import
          // this is rar
          // TODO improve this and parse the CSS to support multiple medias
          content = content.replace(/;|\s*$/, m.media);
        }

        externalsSource.add(content);
        externalsSource.add('\n');
      } else {
        if (m.media) {
          source.add(`@media ${m.media} {\n`);
        }

        if (m.sourceMap) {
          source.add(
            new SourceMapSource(
              content,
              m.readableIdentifier(requestShortener),
              m.sourceMap.toString()
            )
          );
        } else {
          source.add(
            new RawSource(content, m.readableIdentifier(requestShortener))
          );
        }
        source.add('\n');

        if (m.media) {
          source.add('}\n');
        }
      }
    }

    return new ConcatSource(externalsSource, source);
  }
}

MiniCssExtractPlugin.loader = require.resolve('./loader');

export default MiniCssExtractPlugin;