TypeError: Cannot assign to read only property '0' of string 'vue-loader'

[alexander-heimbuch]

After the update to Webpack 4 (4.6) the webpack build fails with the following error right on start of the process:

TypeError: Cannot assign to read only property '0' of string 'vue-loader'
    at VueLoaderPlugin.apply (/path/to/my/project/node_modules/vue-loader/lib/plugin.js:97:42)
    at webpack (/path/to/my/project/node_modules/webpack/lib/webpack.js:37:12)
    at processOptions (/path/to/my/project/node_modules/webpack-cli/bin/webpack.js:436:16)
    at yargs.parse (/path/to/my/project/node_modules/webpack-cli/bin/webpack.js:512:3)
    at Object.parse (/path/to/my/project/node_modules/yargs/yargs.js:552:18)
    at /path/to/my/project/node_modules/webpack-cli/bin/webpack.js:217:8
    at Object.<anonymous> (/path/to/my/project/node_modules/webpack-cli/bin/webpack.js:514:3)
    at Module._compile (module.js:643:30)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
    at Module.require (module.js:587:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/path/to/my/project/node_modules/webpack/bin/webpack.js:80:2)
    at Module._compile (module.js:643:30)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
    at Function.Module.runMain (module.js:684:10)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

If I remove the VueLoaderPlugin from my plugins the build runs till the vue files needs to be parsed.

Corresponding webpack config:

{
  mode: 'production',

  entry: {
    embed: path.resolve(sourceDir, 'embed', 'embed.js'),
    window: path.resolve(sourceDir, 'embed', 'window.js'),
    share: path.resolve(sourceDir, 'embed', 'share.js'),
    vendor: path.resolve(sourceDir, 'vendor.js')
  },

  output: {
    path: distDir,
    filename: '[name].js',
    publicPath: ''
  },

  resolve: {
    extensions: ['*', '.js', '.vue', '.json'],
    alias: {
      'vue$': 'vue/dist/vue.common.js',
      store: path.resolve(sourceDir, 'store'),
      utils: path.resolve(sourceDir, 'utils'),
      shared: path.resolve(sourceDir, 'components', 'shared'),
      icons: path.resolve(sourceDir, 'components', 'icons'),
      lang: path.resolve(sourceDir, 'lang'),
      core: path.resolve(sourceDir, 'core'),
      styles: path.resolve(sourceDir, 'styles')
    }
  },

  module: {
    rules: [{
      test: /\.vue$/,
      use: 'vue-loader'
    }, {
      test: /\.js?$/,
      loader: 'babel-loader'
    }, {
        test: /\.scss$/,
        use: [
          MiniCssExtractPlugin.loader,
          'css-loader',
          'scss-loader'
        ]
    }, {
      test: /\.(png|jpg|gif|jpeg|svg)$/,
      loader: 'file-loader',
      options: {
        name: '[name].[ext]?[hash]'
      }
    }, {
      test: /\.(eot|svg|ttf|woff|woff2)$/,
      loader: 'file-loader',
      options: {
        name: 'fonts/[name].[ext]?[hash]'
      }
    }]
  },

  plugins: [
      new VueLoaderPlugin(),
      new MiniCssExtractPlugin({
        filename: 'style.css'
      }),

      new webpack.DefinePlugin({
        BASE: JSON.stringify(get(process.env, 'BASE', '.'))
      }),

      new UglifyJsPlugin()
   ]
}

[vue-bot]

Hello, your issue has been closed because it does not conform to our issue requirements. In order to ensure every issue provides the necessary information for us to investigate, we require the use of the Issue Helper when creating new issues. Thank you!

[sgehrman]

same problem. Need answers, not authoritarian bots.

[yyx990803]

@sgehrman or maybe you can try to respect the issue requirements and follow the instructions?

[sgehrman]

I think the solution is to use "loader" instead of "use" for single loader strings

I had:
use: 'vue-loader'
use: 'eslint-loader'

but should have had
loader: 'vue-loader'
loader: 'eslint-loader'

use is for arrays, loader is for a single string it seems based on my quick googling.

Was that so hard? Did it really require two closed issues, codepen repros, and telling me to respect the rules?? Sorry, I didn't have helicopter parents. I'm not brainwashed to blindly follow authority and ridiculous rules that make no sense.

[yyx990803]

@sgehrman please don't ever come back.

[yyx990803]

@sgehrman It's not about authority, it's about respecting the rules set by the maintainers who spent time working on something and giving it to you for free, who have to deal with hundreds of issues every week, and had to set down these rules to be able to stay efficient and sane. If you can't deal with it, go use whatever other software that solves your problems. I don't need users like you.