webpack-dev-server: webpack-dev-server stops watching files for changes on .js syntax error

  • Operating System: Windows 10
  • Node Version: v14.16.1
  • NPM Version: 6.14.12
  • webpack Version: 5.31.0
  • webpack-dev-server Version: 3.11.2
  • Browser: Version 89.0.4389.114 (Official Build) (64-bit)
  • This is a bug

Code

const path = require('path')
const HTMLWebpackPlugin = require('html-webpack-plugin')
const CopyPlugin = require('copy-webpack-plugin')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const ESLintPlugin = require('eslint-webpack-plugin')

const isProd = process.env.NODE_ENV === 'production'
const isDev = !isProd

const filename = (ext) =>
  isDev ? `bundle.${ext}` : `bundle.[fullhash].${ext}`

module.exports = {
  context: path.resolve(__dirname, 'src'),
  mode: 'development',
  entry: ['@babel/polyfill', './index.js'],
  output: {
    filename: filename('js'),
    path: path.resolve(__dirname, 'dist'),
    clean: true,
  },
  resolve: {
    extensions: ['.js'],
    alias: {
      '@': path.resolve(__dirname, 'src'),
      '@core': path.resolve(__dirname, 'src/core'),
    },
  },
  devtool: isDev ? 'source-map' : false,
  devServer: {
    port: 8080,
    hot: isDev,
    watchContentBase: true,
  },
  plugins: [
    new ESLintPlugin(),
    new HTMLWebpackPlugin({
      template: 'index.html',
      filename: 'index.html',
      minify: {
        removeComments: isProd,
        collapseWhitespace: isProd,
      },
    }),
    new CopyPlugin({
      patterns: [
        {
          from: path.resolve(__dirname, 'src/favicon.ico'),
          to: path.resolve(__dirname, 'dist'),
        },
      ],
    }),
    new MiniCssExtractPlugin({
      filename: filename('css'),
    }),
  ],
  target: 'web',
  module: {
    rules: [
      {
        test: /\.s[ac]ss$/i,
        use: [MiniCssExtractPlugin.loader, 'css-loader', 'sass-loader'],
      },
      {
        test: /\.m?js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env'],
          },
        },
      },
    ],
  },
}

deps:

{
  "devDependencies": {
    "@babel/core": "^7.13.14",
    "@babel/eslint-parser": "^7.13.14",
    "@babel/preset-env": "^7.13.12",
    "babel-loader": "^8.2.2",
    "copy-webpack-plugin": "^8.1.0",
    "cross-env": "^7.0.3",
    "css-loader": "^5.2.0",
    "eslint": "^7.23.0",
    "eslint-config-google": "^0.14.0",
    "eslint-webpack-plugin": "^2.5.3",
    "html-webpack-plugin": "^5.3.1",
    "mini-css-extract-plugin": "^1.4.0",
    "sass": "^1.32.8",
    "sass-loader": "^11.0.1",
    "webpack": "^5.31.0",
    "webpack-cli": "^4.6.0",
    "webpack-dev-server": "v3.11.2"
  },
  "dependencies": {
    "@babel/polyfill": "^7.12.1",
    "normalize.css": "^8.0.1"
  }
}

index.js

console.log('working!')
cosole.log('working!') // trigger an error

Expected Behavior

webpack-dev-server successfully refreshes the page or places in changes

Actual Behavior

A syntax error breaks watching files and webpack-dev-server stops showing any new changes (but compiles them, terminal tells this) until the page is refreshed manually with F5

About this issue

  • Original URL
  • State: closed
  • Created 3 years ago
  • Comments: 37 (21 by maintainers)

Most upvoted comments

It is fixed in webpack-dev-server@4-beta, we have the watchFiles option

I tried making it on the sandbox but I can’t for the death of me make it run, if you can figgure it out, be my guest: https://codesandbox.io/s/webpack-sample-ub8ue?file=/webpack.config.js

alternatively, find it on my github: https://github.com/DelliriumX/webpack-reload-clone

It is a bit convoluted, but I’ve cut away a lot of the custom build thing out of it so some things might not make much sense, still doesn’t work. I am not sure if my start script (package-json) or devServer config is correct, but it refuses to reload, I am open to suggestions.

Can you provide example/reproducible test repo?

I can try to mock something up but will take some time, as the entire thing is super convoluted, give me 10 minutes or so to try to scrape from where I am and get it up as a new repo

I need investigate, WIP on this

Bug, we need to set optimization.emitOnErrors: false when hmr enabled by default, workaround:

optimization: {
  emitOnErrors: false
}