index.js

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

import webpack, { version as webpackVersion } from 'webpack';

import validateOptions from 'schema-utils';

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

// webpack 5 exposes the sources property to ensure the right version of webpack-sources is used
const { ConcatSource, SourceMapSource, OriginalSource } =
  // eslint-disable-next-line global-require
  webpack.sources || require('webpack-sources');

const {
  Template,
  util: { createHash },
} = webpack;

const isWebpack4 = webpackVersion[0] === '4';

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

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

class MiniCssExtractPlugin {
  constructor(options = {}) {
    validateOptions(schema, options, 'Mini CSS Extract Plugin');

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

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

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

  apply(compiler) {
    compiler.hooks.thisCompilation.tap(pluginName, (compilation) => {
      compilation.dependencyFactories.set(
        CssDependency,
        new CssModuleFactory()
      );

      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 ||
              (({ chunk: chunkData }) =>
                this.options.moduleFilename(chunkData));

            if (renderedModules.length > 0) {
              result.push({
                render: () =>
                  this.renderContentAsset(
                    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(
                    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 renderedModules = Array.from(
              this.getChunkModules(chunk, chunkGraph)
            ).filter((module) => module.type === MODULE_TYPE);

            const filenameTemplate =
              chunk.filenameTemplate ||
              chunk.hasRuntime() ||
              chunk.isOnlyInitial()
                ? ({ chunk: chunkData }) =>
                    this.options.moduleFilename(chunkData)
                : this.options.chunkFilename;

            if (renderedModules.length > 0) {
              result.push({
                render: () =>
                  this.renderContentAsset(
                    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 { hashFunction, hashDigest, hashDigestLength } = outputOptions;
        const hash = createHash(hashFunction);

        for (const m of this.getChunkModules(chunk, chunkGraph)) {
          if (m.type === MODULE_TYPE) {
            m.updateHash(hash, { chunkGraph });
          }
        }

        const { contentHash } = chunk;

        contentHash[MODULE_TYPE] = hash
          .digest(hashDigest)
          .substring(0, hashDigestLength);
      });

      const { mainTemplate } = compilation;

      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 maintemplateObject = isWebpack4 ? mainTemplate : compilation;
            const chunkMaps = chunk.getChunkMaps();
            const { crossOriginLoading } = maintemplateObject.outputOptions;
            const linkHrefPath = maintemplateObject.getAssetPath(
              JSON.stringify(this.options.chunkFilename),
              {
                hash: isWebpack4
                  ? `" + ${mainTemplate.renderCurrentHashCode(hash)} + "`
                  : `" + ${webpack.RuntimeGlobals.getFullHash} + "`,
                hashWithLength: (length) =>
                  isWebpack4
                    ? `" + ${mainTemplate.renderCurrentHashCode(
                        hash,
                        length
                      )} + "`
                    : `" + ${webpack.RuntimeGlobals.getFullHash} + "`,
                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 = ${
                    isWebpack4
                      ? mainTemplate.requireFn
                      : webpack.RuntimeGlobals.require
                  }.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");',
                  'linkTag.rel = "stylesheet";',
                  'linkTag.type = "text/css";',
                  'linkTag.onload = resolve;',
                  'linkTag.onerror = function(event) {',
                  Template.indent([
                    'var request = event && event.target && event.target.src || fullhref;',
                    'var err = new Error("Loading CSS chunk " + chunkId + " failed.\\n(" + request + ")");',
                    'err.code = "CSS_CHUNK_LOAD_FAILED";',
                    'err.request = request;',
                    'delete installedCssChunks[chunkId]',
                    'linkTag.parentNode.removeChild(linkTag)',
                    'reject(err);',
                  ]),
                  '};',
                  'linkTag.href = fullhref;',
                  crossOriginLoading
                    ? Template.asString([
                        `if (linkTag.href.indexOf(window.location.origin + '/') !== 0) {`,
                        Template.indent(
                          `linkTag.crossOrigin = ${JSON.stringify(
                            crossOriginLoading
                          )};`
                        ),
                        '}',
                      ])
                    : '',
                  'var head = document.getElementsByTagName("head")[0];',
                  'head.appendChild(linkTag);',
                ]),
                '}).then(function() {',
                Template.indent(['installedCssChunks[chunkId] = 0;']),
                '}));',
              ]),
              '}',
            ]);
          }

          return source;
        }
      );
    });
  }

  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;
  }

  renderContentAsset(compilation, chunk, modules, requestShortener) {
    let usedModules;

    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;
    }

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

    for (const m of usedModules) {
      if (/^@import url/.test(m.content)) {
        // HACK for IE
        // http://stackoverflow.com/a/14676665/1458162
        let { content } = m;

        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(
              m.content,
              m.readableIdentifier(requestShortener),
              m.sourceMap
            )
          );
        } else {
          source.add(
            new OriginalSource(
              m.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;