编程式 Webpack 和 Jest (ESM)：无法解析没有“.js”文件扩展名的模块

Question

我以编程方式使用 webpack，结合 typescript、ESM 和 jest。在一个玩笑测试中，我.js在导入 ES 模块时因不包含文件扩展名而收到错误。例如：

    Module not found: Error: Can't resolve 'modulename' in '/path/components'
    Did you mean 'modulename.js'?
    BREAKING CHANGE: The request 'modulename' failed to resolve only because it was resolved as fully specified
    (probably because the origin is strict EcmaScript Module, e. g. a module with javascript mimetype, a '*.mjs' file, or a '*.js' file where the package.json contains '"type": "module"').
    The extension in the request is mandatory for it to be fully specified.
    Add the extension to the request.

有问题的模块确实"type": "module"在其package.json. 我尝试添加.js到导入中，但没有帮助。

我用以下方式调用笑话：

node --experimental-vm-modules --experimental-specifier-resolution=node node_modules/jest/bin/jest.js

正如文档中建议的那样（除了 webpack 之外其他一切都有效）。请注意，我尝试过使用和不使用--experimental-specifier-resolution=node（这在其他类似情况下有所帮助）。

关于如何让 webpack 工作有什么想法吗？提前致谢！

注意：一切正常，直到全部转换为 ESM！现在只有程序化 webpack 不起作用。

网页包配置：

  {
    entry,
    target: 'web',
    output: {
      path: outputDir,
      filename: '[name].js',
    },
    mode: process.env.NODE_ENV as 'development' | 'production' | 'none' | undefined,
    resolve: {
      extensions: [
        '.ts',
        '.tsx',
        '.js',
        '.jsx',
        '.ttf',
        '.eot',
        '.otf',
        '.svg',
        '.png',
        '.woff',
        '.woff2',
        '.css',
        '.scss',
        '.sass',
      ],
    },
    module: {
      rules: [
        {
          test: /\.(ttf|eot|otf|svg|png)$/,
          loader: 'file-loader',
        },
        {
          test: /\.(woff|woff2)$/,
          loader: 'url-loader',
        },
        {
          test: /\.(js|jsx|ts|tsx)$/,
          exclude: /node_modules/,
          loader: 'babel-loader',
          options: {
            sourceType: 'unambiguous',
            presets: [
              [
                '@babel/preset-env',
                {
                  corejs: '3.0.0,',
                  useBuiltIns: 'usage',
                },
              ],
              '@babel/preset-react',
              '@babel/preset-typescript',
            ],
            plugins: [
              'css-modules-transform',
              [
                'babel-plugin-react-scoped-css',
                {
                  include: '.scoped.(sa|sc|c)ss$',
                },
              ],
              '@babel/plugin-proposal-class-properties',
            ],
          },
        },
        {
          test: /\.(sc|c|sa)ss$/,
          use: [
            'style-loader',
            'css-loader',
            'scoped-css-loader',
            'sass-loader',
          ],
        },
      ],
    },
  }

Answer 1

好的，我在这里找到了解决方案。

基本上，必须在 webpack 配置中添加两件事module.rules：

{
  test: /\.m?js/,
  type: "javascript/auto",
},
{
  test: /\.m?js/,
  resolve: {
    fullySpecified: false,
  },
},

Answer 2

@nerdlinger 的答案对我有用。我有这个 webpack.config.js

module.exports = {
    entry: './src/index.js',
    module: {
        rules: [
            {
                test: /\.(js)$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader'
                }
            }
        ],
    }
    ...
}

我把它改成了这个

module.exports = {
    entry: './src/index.js',
    module: {
        rules: [
            {
                test: /\.(js)$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader'
                },
                resolve: {
                  fullySpecified: false,
                }
            }
        ],
    }
    ...
}