Mini-css-extract-plugin: Question: Multiple JS chunks, single CSS chunk

[AvraamMavridis]

Is it possible to have multiple JS chunks but a single css output file?

My current setup is:

  optimization: {
    minimize: true,
    minimizer: [
      new UglifyJSPlugin({
        uglifyOptions: {
          compress: {
            passes: 2,
          },
          output: {
            comments: false,
          },
        },
      }),
    ],
    splitChunks: {
      chunks: 'all',
      cacheGroups: {
        vendor: {
          filename: 'vendorbundle.js',
          test: m => /node_modules/.test(m.context),
        },
      },
    },
  },

...
...

    new MiniCssExtractPlugin({
      filename: 'styles.css',
    }),

This generates 2 JS files, and 2 css files (styles.css, and 1.styles.css)

What I would like to have is a single css file, is that doable?

[Pierre-Do]

I've been using something like that for the same use-case with success:

  optimization: {
    splitChunks: {
      cacheGroups: {
        default: false,
        // Custom common chunk
        bundle: {
          name: 'commons',
          chunks: 'all',
          minChunks: 3,
          reuseExistingChunk: false,
        },
        // Customer vendor
        vendors: {
          chunks: 'initial',
          name: 'vendors',
          test: 'vendors',
        },
        // Merge all the CSS into one file
        styles: {
          name: 'styles',
          test: /\.s?css$/,
          chunks: 'all',
          minChunks: 1,
          reuseExistingChunk: true,
          enforce: true,
        },
      },
    },
  },

[AvraamMavridis]

Doesnt seem to work for me

[AvraamMavridis]

@Akkenar can you share all of the config file please?

[Pierre-Do]

@AvraamMavridis it seems that I was missing an enforce: true on the rule.

You'll find an example project there: https://github.com/Akkenar/CSS-Single-File-Example

Webpack config:

import webpack from 'webpack';
import path from 'path';
import MiniCssExtractPlugin from 'mini-css-extract-plugin';
import HtmlWebpackPlugin from 'html-webpack-plugin';
import OptimizeCSSAssetsPlugin from 'optimize-css-assets-webpack-plugin';

const vendors = ['react', 'react-dom'];
const isProduction = process.env.NODE_ENV === 'production';

export default {
  name: 'client',
  mode: isProduction ? 'production' : 'development',
  target: 'web',
  entry: {
    bundle: './entry.js',
    vendors,
  },
  context: path.join(__dirname, 'src'),

  stats: {
    // Disable the verbose output on build
    children: false,
  },

  devtool: isProduction ? false : 'inline-cheap-module-eval-source-map',

  output: {
    path: path.join(__dirname, 'target', 'build'),
    filename: '[name].js',
    chunkFilename: '[name].js',
  },

  resolve: {
    extensions: ['.js', '.jsx', '.scss'],
  },

  module: {
    rules: [
      {
        test: /\.jsx?$/,
        exclude: /node_modules/,
        use: ['babel-loader?cacheDirectory'],
      },
      {
        test: /\.scss$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader', 'sass-loader'],
      },
    ],
  },

  optimization: {
    splitChunks: {
      cacheGroups: {
        default: false,
        // Custom common chunk
        bundle: {
          name: 'commons',
          chunks: 'all',
          minChunks: 3,
          reuseExistingChunk: false,
        },
        // Customer vendor
        vendors: {
          chunks: 'initial',
          name: 'vendors',
          test: 'vendors',
        },
        // Merge all the CSS into one file
        styles: {
          name: 'styles',
          test: /\.s?css$/,
          chunks: 'all',
          enforce: true,
        },
      },
    },
  },
  profile: false,

  plugins: [
    new webpack.optimize.ModuleConcatenationPlugin(),
    new MiniCssExtractPlugin({
      filename: '[name].css',
      chunkFilename: '[name].css',
    }),
    new OptimizeCSSAssetsPlugin(),
    new HtmlWebpackPlugin({
      minify: {
        collapseWhitespace: true,
        preserveLineBreaks: true,
        removeComments: true,
      },
      filename: 'index.html',
      template: path.join(__dirname, 'src', 'index.html'),
    }),
  ],
};

[AvraamMavridis]

@Akkenar It doesnt really work:

That is my setup:

const path = require('path');
const loaders = require('./loaders');
const plugins = require('./plugins');
const webpack = require('webpack');
const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const ProgressBarPlugin = require('progress-bar-webpack-plugin');
const frontend = require('../package.json');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

const DIRECTORY = `${__dirname}/../`;

module.exports = {
  mode: 'production',
  devtool: 'source-map',
  entry: {
    app: ['babel-polyfill', path.join(__dirname, './../src/App.js')],
  },
  optimization: {
    minimize: true,
    minimizer: [
      new UglifyJSPlugin({
        uglifyOptions: {
          compress: {
            passes: 2,
          },
          output: {
            comments: false,
          },
        },
      }),
    ],
    splitChunks: {
      chunks: 'all',
      cacheGroups: {
        default: false,
        // Custom common chunk
        bundle: {
          name: 'commons',
          chunks: 'all',
          minChunks: 3,
          reuseExistingChunk: false,
        },
        // Customer vendor
        vendor: {
          filename: 'vendorbundle.js',
          test: m => /node_modules/.test(m.context),
        },
        // Merge all the CSS into one file
        styles: {
          name: 'styles',
          test: /\.s?css$/,
          chunks: 'all',
          minChunks: 1,
          reuseExistingChunk: true,
          enforce: true,
        },
      },
    },
  },
  output: {
    filename: 'bundle.js',
    path: path.join(DIRECTORY, './artifacts/'),
    chunkFilename: 'chunk-[name]-[hash].js',
    publicPath: '/savingglobal/assets/dist/js/',
  },
  plugins: plugins.concat([
    new ProgressBarPlugin(),

    /* Css specific plugins */
    new MiniCssExtractPlugin({
      filename: '[name].css',
      chunkFilename: '[name].css',
    }),
    new OptimizeCssAssetsPlugin({
      cssProcessor: require('cssnano'),
      cssProcessorOptions: {
        discardComments: { removeAll: true },
        zindex: false,
      },
      canPrint: true,
    }),
    /* Define the enviroment */
    new webpack.DefinePlugin({
      PRODUCTION: JSON.stringify(true),
      'process.env.NODE_ENV': JSON.stringify('production'),
      'process.env': {
        NODE_ENV: JSON.stringify('production'),
        frontend_version: JSON.stringify(frontend.version),
      },
    }),
    new webpack.optimize.ModuleConcatenationPlugin(),
  ]),
  module: {
    rules: loaders.concat([
      {
        test: /\.scss$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader', 'sass-loader'],
      },
    ]),
  },
  resolve: {
    alias: {
      'raisin-frontend': path.resolve(__dirname, '../../'),
      'ui-lib': '@raisin/ui-lib',
      assets: path.resolve(__dirname, '../assets'),
    },
    extensions: ['.js', '.jsx', '.json', '.scss'],
  },
};

[Pierre-Do]

It seems that the vendors are still generated for the CSS.

You could try:

• Add vendors: false, in cacheGroups, see if this disables the vendor~ generation
• Try to add priorities to the rules within cacheGroups, see if you can have the style one being more greedy.

[sokra]

Do you want to send a PR adding this to the documentation?

minChunks: 1, and reuseExistingChunk: true, are not needed.

[Pierre-Do]

Thanks for your feedback @sokra .

I'll send a PR whenever I find time.

[dtothefp]

duplicate here https://github.com/webpack-contrib/mini-css-extract-plugin/issues/41

[Cople]

how to prevent styles.js? it's a redundant file.

[sokra]

how to prevent styles.js? it's a redundant file.

This need to be solved on webpack side

[aboeglin]

Is this supposed to work at the moment ?

[alexander-akait]

@aboeglin no, please create issue in webpack repo with minimum reproducible test repo. thanks

[mnpenner]

I'm still getting a CSS file for every chunk with

styles: {
    name: 'styles',
    test: /\.(css|less)$/, // not sure if .less is necessary or its already been compiled at this point
    chunks: 'all',
    enforce: true
}

Which seems to be breaking my CSS CSS break was my own dumb fault. cssnano was shrinking my z-indexes. I still haven't managed to produce a single output CSS file though. Probably something else I messed up...

[klis87]

I also cannot make it work, whats happens for me is that I have multiple entries (multi real web pages SPA), and after any combination suggested here, I end up with unnecessary styles.js chunk, and, whats worse, without vendor and commons chunks which are generated otherwise.

For now I migrated back to extract-text-plugin@next, which works fine.

[mnpenner]

It should be jsx? unless you're using jsx and jx extensions, which would be
weird.

On Tue, Aug 7, 2018, 7:59 AM Iuriy Budnikov [e-mail]
wrote:

@mnpenner https://github.com/mnpenner,
Try to set extension test: /.js?x$/ for js files.
It works for me.

optimization: {
splitChunks: {
cacheGroups: {
commons: {
test: /[\/]node_modules[\/]/,
name: 'vendor',
chunks: 'all',
test: /.js?x$/,
},
styles: {
name: 'styles',
test: /.s?css$/,
chunks: 'all',
enforce: true,
},
},
}
},

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[Iuriy-Budnikov]

@mnpenner , please ignore my message. It doesn't resolve the issue.

[ghost]

@sokra
Why the issue has closed? This is not fixed. At least point people to a direction.

[anastasiap]

Non of the above proposed solutions worked for me.

I solved the issue by using underscore for scss files in components and then importing it in style.scss the usual way.

• components
  -- About
  --- _about.scss
  --- About.vue
  --- About.ts

• scss
  -- style.scss

@import '../components/About/about';

[oswaldofreitas]

If someone found an answer please post it here.

[rtxanson]

Give the explanation here a shot: https://github.com/webpack-contrib/mini-css-extract-plugin/issues/257#issuecomment-421625285

I seemed to be having a similar problem and this fixed it.

[rnicholus]

Can this please be re-opened until a solution is in place?

[alexander-akait]

@rnicholus solution of what? use splitChunks and configure chunks how you want (one, two, one hundred)

[rnicholus]

I've followed that guidance, and it didn't seem to have any effect. This seems to have been a problem for other posters in this issue as well.

[2-5]

This works for me, change the test regular expression to only match .js (and not something like .css):

optimization: {
  splitChunks: {
    cacheGroups: {
      vendor: {
        test: /[\\/]node_modules[\\/].*\.js$/,
        name: 'vendors',
        chunks: 'all',
      },
    },
  },
},

[rnicholus]

@2-5 After adding that to my webpack config, I'm still seeing about 50 CSS chunks.

[ShubhamChodankar026531]

To Create a Single css file and create chunk of vendor.js file, can use the following configuration.

optimization: {
      splitChunks: {
         cacheGroups: {
           commons: {
             test: /[\\/]node_modules[\\/](.(?!.*\.css$))*$/,
             name: 'vendors',
             chunks: 'all'
           }
         },
       }
  }

the regex is different from one mentioned in above comments : test: /[\\/]node_modules[\\/].*\.js$/,
in a way that it takes all files apart from .css files in vendors.js...
can use either one based on file types used in project.
this is compatible with Webpack version > 4 at the time.

[matzeeable]

Stumbled over the same problem but I go one step further because my script imports also .scss and .less files from vendors:

splitChunks: {
    vendor: {
        // [...]
        test: /node_modules.*(?<!\.css)(?<!\.scss)(?<!\.less)$/
        // [...]
    }
}

[StNekroman]

Very bad bug.
It's impossible to fetch all styles to one file.

Found the reason - it was due to my custom webpack config, where I was combining chunks by issuer file.
But for one chunk the issuer was completely separate - that's why some styles gone to separate bundle.

[temple]

@StNekroman, have you tried the formula suggested in the PR #60 , which is already merged?
It works for me, combining in one file shared styles among different entry points dependency graphs, no matter if are vendors or local app ones.

[StNekroman]

@temple nevermind, it was my issue - comment updated.