webpack.config.js

// webpack.config.js

'use strict';

const path = require('path');
const webpack = require('webpack');
const {styles} = require('@ckeditor/ckeditor5-dev-utils');

module.exports = {
  // https://webpack.js.org/configuration/entry-context/
  entry: './app.js',

  // https://webpack.js.org/configuration/output/
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'bundle.js'
  },

  module: {
    rules: [
      {
        test: /ckeditor5-[^/\\]+[/\\]theme[/\\]icons[/\\][^/\\]+\.svg$/,

        use: ['raw-loader']
      },
      {
        test: /ckeditor-deepl-module[/\\]theme[/\\]icons[/\\][^/\\]+\.svg$/,

        use: ['raw-loader']
      },
      {
        test: /ckeditor5-[^/\\]+[/\\]theme[/\\].+\.css$/,

        use: [
          {
            loader: 'style-loader',
            options: {
              injectType: 'singletonStyleTag',
              attributes: {
                'data-cke': true
              }
            }
          },
          'css-loader',
          {
            loader: 'postcss-loader',
            options: {
              postcssOptions: styles.getPostCssConfig({
                themeImporter: {
                  themePath: require.resolve('@ckeditor/ckeditor5-theme-lark')
                },
                minify: true
              })
            }
          }
        ]
      }
    ]
  },

  // Useful for debugging.
  devtool: 'source-map',

  // By default webpack logs warnings if the bundle is bigger than 200kb.
  performance: {hints: false},

  plugins: [
    new webpack.DefinePlugin({
      'process.env': JSON.stringify(process.env)
    })
  ]
};