SetModuleTemplatePlugin

SetModuleTemplatePlugin.js

const { ConcatSource } = require('webpack-sources');
const RuntimeGlobals = require('webpack/lib/RuntimeGlobals');
const JavascriptModulesPlugin = require('webpack/lib/javascript/JavascriptModulesPlugin');

/** @typedef {import("./Compiler")} Compiler */

class SetModuleTemplatePlugin {
  /**
   * @param {string} moduleMethod the accessor where the library is exported
   * @param {boolean} moduleName specify copying the exports
   */
  constructor(moduleMethod, moduleName) {
    /** @type {string} */
    this.moduleMethod = moduleMethod;
    /** @type {boolean} */
    this.moduleName = moduleName;
  }

  /**
   * @param {Compiler} compiler the compiler instance
   * @returns {void}
   */
  apply(compiler) {
    const FlagEntryExportAsUsedPlugin = require('webpack/lib/FlagEntryExportAsUsedPlugin');
    new FlagEntryExportAsUsedPlugin(true, 'used a library export').apply(
      compiler
    );

    compiler.hooks.thisCompilation.tap(
      'SetModuleTemplatePlugin',
      compilation => {
        compilation.hooks.additionalTreeRuntimeRequirements.tap(
          'LibraryTemplatePlugin',
          (chunk, set) => {
            set.add(RuntimeGlobals.returnExportsFromRuntime);
          }
        );

        const hooks = JavascriptModulesPlugin.getCompilationHooks(compilation);

        hooks.render.tap(
          'SetModuleTemplatePlugin',
          (source, { chunk, chunkGraph }) => {
            if (chunkGraph.getNumberOfEntryModules(chunk) === 0) return source;
            const moduleMethod = compilation.getPath(this.moduleMethod, {
              chunk,
            });
            return new ConcatSource(
              `${moduleMethod}('${this.moduleName}',`,
              source,
              ')'
            );
          }
        );

        hooks.chunkHash.tap(
          'SetModuleTemplatePlugin',
          (chunk, hash, { chunkGraph }) => {
            if (chunkGraph.getNumberOfEntryModules(chunk) === 0) return;
            hash.update('set var');
            const moduleMethod = compilation.getPath(this.moduleMethod, {
              chunk,
            });
            hash.update(`${moduleMethod}`);
            hash.update(`${this.moduleName}`);
          }
        );
      }
    );
  }
}

module.exports = SetModuleTemplatePlugin;