Webpack css-loader失败：“您可能需要一个合适的加载器来处理这种文件类型。”

Question

I'm building a React app that uses TypeScript and Webpack 4. I'm trying to import a CSS file from react-select , and I'm getting the generic error:

ERROR in ./node_modules/react-select/dist/react-select.css
Module parse failed: Unexpected token (8:0)
You may need an appropriate loader to handle this file type.
|  * MIT License: https://github.com/JedWatson/react-select
| */
| .Select {
|   position: relative;
| }
 @ ./src/App.react.tsx 28:0-45
 @ ./src/Root.react.tsx
 @ ./src/index.tsx
 @ multi (webpack)-dev-server/client?http://localhost:3000 webpack/hot/dev-server ./src/index.tsx

I had a similar issue with trying to add a loader for .graphql files before punting it... I imagine the issues are related; something with my config must be off that's failing to leverage these extra loaders.

I took the barebones css-loader setup straight from https://github.com/webpack-contrib/css-loader .

The file-loader I have is working perfectly fine.

Here's what I think the relevant snippets of code are:

From webpack.common.ts :

const config: webpack.Configuration = {
  module: {
    rules: [
      ...
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader']
      },
    ],
  },
  resolve: {
    extensions: ['.ts', '.tsx', '.js', '.css'],
  },
  ...
};

From App.react.tsx :

import 'react-select/dist/react-select.css';
...

But guessing there's something outside of that context that's causing the problem. More context...

webpack.common.ts

import * as HTMLPlugin from 'html-webpack-plugin';
import * as CleanWebpackPlugin from 'clean-webpack-plugin';
import * as webpack from 'webpack';

const config: webpack.Configuration = {
  // Root TS file for bundling
  entry: './src/index.tsx',
  module: {
    rules: [
      // Bundle files (e.g. images)
      {
        test: /\.(png|jpg|gif)$/,
        use: ['file-loader'],
      },
      // Transpile & type check with babel/typescript loader
      {
        test: /\.tsx?$/,
        use: [
          {
            // Need babel for React HMR support (otherwise could drop babel and use just typescript)
            loader: 'babel-loader',
            options: {
              babelrc: true,
              plugins: ['react-hot-loader/babel'],
            },
          },
          'ts-loader',
        ],
      },
      // Handle .css files
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader']
      },
    ],
  },
  // Enable served source maps
  devtool: 'inline-source-map',
  resolve: {
    // Include all these extensions in processing (note we need .js because not all node_modules are .ts)
    extensions: ['.ts', '.tsx', '.js', '.css'],
  },
  // Webpack Dev Server for running locally
  devServer: {
    // Play nicely with react-router
    historyApiFallback: true,
    port: 3000,
    // Enable hot module reloading (HMR)
    hot: true,
  },
  plugins: [
    // Cleans the build folder per-build/reload
    new CleanWebpackPlugin(['dist']),
    // Builds the .html file for entering into bundle
    new HTMLPlugin({
      template: 'INDEX_TEMPLATE.html',
    }),
    // HMR plugins
    new webpack.NamedModulesPlugin(),
    new webpack.HotModuleReplacementPlugin(),
    // Prevents webpack watch from going into infinite loop (& stopping on retry) due to TS compilation
    new webpack.WatchIgnorePlugin([
      /\.js$/,
      /\.d\.ts$/,
    ]),
  ],
};

export default config;

tsconfig.json

{
  "compilerOptions": {
    // Required option for react-hot-loader
    "target": "es6",
    // Required option for react-hot-loader
    "module": "commonjs",
    "strict": true,
    "jsx": "react",
    // Absolute imports start from here
    "baseUrl": ".",
    "sourceMap": true
  }
}

Please let me know if there's anything else worth noting that could be part of the problem... Thanks!

Answer 1

OP here. Appears to have been a silly issue: I clicked "Compile All" on the WebStorm TypeScript compiler and the css-loader started working fine. So I guess webpack was using an un-updated webpack.common.js file instead of the webpack.common.ts file in my question.

Trying to understand why it was referencing the compiled .js file even though my command was:

webpack-dev-server --mode development --open --config config/webpack.development.ts

Likely something to do with the fact that I was using webpack-merge and so importing webpack.common: import common from './webpack.common'; . Sans extension in the import, for some reason it must default to .js .

If anyone else runs into this issue, useful tip from this question Configure WebStorm to delete *.ts *.js *.js.map all together : output the generated files (.js and .js.map) to a different folder using the outDir option in tsconfig.json. The build folder can then easily be cleaned output the generated files (.js and .js.map) to a different folder using the outDir option in tsconfig.json. The build folder can then easily be cleaned

Will report back if I find out anything more.