FederatedStartupCodePlugin.js

FederatedStartupCodePlugin.js

const fs = require("fs");
const path = require("path");

const Template = require("webpack/lib/Template");
const SingleEntryPlugin = require("webpack/lib/SingleEntryPlugin");
const VirtualModulesPlugin = require("webpack-virtual-modules");

const PLUGIN_NAME = "FederatedStartupCodePlugin";

/**
 * @typedef {object} FederatedStartupCodeOptions
 * @property {string} name
 * @property {code | undefined} code
 */

class FederatedStartupCodePlugin {
  /**
   *
   * @param {FederatedStartupCodeOptions} options
   */
  constructor(options) {
    if (!options) {
      throw new Error("No options provided.");
    }

    if (!options.name) {
      throw new Error("No name provided.");
    }

    this._name = options.name;
    this._modulePath = `./${options.name}-startup.js`;
    this._code = options.code;
  }

  writeCode(code) {
    this._code = code;
  }

  /**
   * @param {import("webpack").Compiler} compiler
   */
  apply(compiler) {
    const virtualModules = new VirtualModulesPlugin({
      [this._modulePath]: "",
    });

    compiler.options.entry =
      typeof compiler.options.entry === "object"
        ? Object.assign({}, compiler.options.entry, {
            [this._name]: { import: [this._modulePath] },
          })
        : {
            main: compiler.options.entry,
            [this._name]: { import: [this._modulePath] },
          };

    compiler.hooks.compile.tap(PLUGIN_NAME, () => {
      const code = Template.asString([
        "const exports = (() => {",
        Template.indent([
          "return Object.keys(__webpack_modules__).reduce((containerModule, moduleId) => {",
          Template.indent([
            "if (moduleId !== module.id) {",
            Template.indent([
              "const currentModule = __webpack_require__(moduleId);",
              `if (typeof currentModule.get === "function" && typeof currentModule.init === "function") {`,
              Template.indent(["return currentModule;"]),
              "}",
            ]),
            "}",
            "return containerModule;",
          ]),
          "}, {});",
        ]),
        "})();",

        "((exports) => {",
        Template.indent(this._code || ""),
        "})(exports);",

        "module.exports = exports;",
      ]);

      virtualModules.writeModule(this._modulePath, code);
    });

    virtualModules.apply(compiler);
  }
}

module.exports = FederatedStartupCodePlugin;