javascript - 我想动态加载到入口点的 Webpack 捆绑模块

Question

下面的代码似乎使用了 dynamic import :

(function executeApplication(): void {

  const loadDataButton: HTMLElement | null = document.getElementById("LoadDataButton");
  if (loadDataButton !== null) {
    loadDataButton.addEventListener("click", (): void => {
      (async function handler(): Promise<void> {
        console.log("Checkpoint 1");
        const loadedValue: string = await loadDataOnDemand();
        console.log(loadedValue);
      })().catch((): void => { /* */ });
    });
  }
})();


async function loadDataOnDemand(): Promise<string> {

  console.log("Checkpoint 2");
  const MODULE: { default: string; DYNAMICALLY_LOADED_CONST_FROM_TS_MODULE: string; } =
      await import("./DynamicLoadingTesting/TypeScriptModuleForDynamicLoading");
  console.log("Checkpoint 3");
  console.log(MODULE);


  return MODULE.DYNAMICALLY_LOADED_CONST_FROM_TS_MODULE;
}

但是实际上 TypeScriptModuleForDynamicLoading.ts 已经被捆绑到入口点:

FrontendLogicPreProcessingTesting:
  asset FrontendLogicPreProcessingTesting.js 11.2 KiB [emitted] (name: FrontendLogicPreProcessingTesting)
  ./FrontendLogicPreProcessingTesting.ts 2.28 KiB [built] [code generated]
  ./DynamicLoadingTesting/TypeScriptModuleForDynamicLoading.ts 419 bytes [built] [code generated]
  FrontendLogicPreProcessingTesting (webpack 5.4.0) compiled successfully in 710 ms

没有 webpack 错误，在浏览器中的输出似乎是正确的:

我的 Webpack 配置:

{
  name: 'FrontendLogicPreProcessingTesting',
  context: 'D:\\IntelliJ IDEA\\XXXXX\\ProjectBuildingCommonTest\\00-Source\\FrontendLogicPreProcessingTesting'
,
  target: 'web',
  entry: {
    FrontendLogicPreProcessingTesting: 'D:/IntelliJ IDEA/XXXXX/ProjectBuildingCommonTest/00-Source/FrontendLogic
PreProcessingTesting/FrontendLogicPreProcessingTesting.ts'
  },
  output: {
    path: 'D:\\IntelliJ IDEA\\XXXXX\\ProjectBuildingCommonTest\\01-DevelopmentBuild\\FrontendLogicPreProcessin
gTesting',
    publicPath: './',
    filename: '[name].js',
    chunkFilename: 'loading_on_demand/partial__[id].js'
  },
  mode: 'development',
  watch: true,
  devtool: 'eval-cheap-source-map',
  module: {
    rules: [
      [Object], [Object],
      [Object], [Object],
      [Object], [Object],
      [Object], [Object],
      [Object]
    ]
  },
  resolve: {
    extensions: [ '.mjs', '.js', '.ts' ],
    alias: { vue: 'vue/dist/vue.common.js' }
  },
  plugins: [
    DefinePlugin { definitions: [Object] },
    ForkTsCheckerWebpackPlugin { options: [Object] },
  ],
  optimization: { minimize: false, emitOnErrors: true }
}

我使用的是 webpack 5.x.x.，但在使用 4.x.x 时遇到了同样的问题。

我的 TypeScript 配置:

{
  "compilerOptions": {

    "target": "es2017",
    "strict": true,

    "module": "CommonJS",
    "moduleResolution": "node",
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "allowJs": false,

    "experimentalDecorators": true,

    "baseUrl": "./",
    "paths": {

    },

    "noUnusedParameters": true,
    "noImplicitReturns": true
  }
}

动态加载还没有满足哪些条件？

Answer 1

您当前正在 tsconfig.json 中使用 module: "CommonJS"，这将导致所有动态 import() 被转换为require() 在 Webpack 真正看到它们之前调用。为了让 Webpack 能够生成新的 block ，Webpack 必须看到动态的 import() 调用。

设置 module: "esnext" 将使动态 import() 不会转换为 require()，因此 Webpack可以妥善处理它们。