webpack.config.js

const path = require('path');
const CopyWebpackPlugin = require('copy-webpack-plugin');

module.exports = {
    entry: {
        bundle: [ './sample/app.js' ]
      },
    output: {
        path: __dirname + '/public',
        filename:'app.js',
        // library: "bpmn",
        //  libraryTarget: "umd"
      },
  module: {
    rules: [{
        test: /\.bpmn$/,
        use: 'raw-loader'
      }]
  },
  plugins: [
    new CopyWebpackPlugin({
      patterns: [
        {
          from: "**",
          to({ context, absoluteFilename }) {
            return Promise.resolve("assets/bpmn-js");
          },
          context:"src/vendor/bpmn-js/assets"
        },
        {
          from: "src/vendor/bpmn-propertyPanel/assets/**",
          to({ context, absoluteFilename }) {
            return Promise.resolve("assets/bpmn-propertyPanel/[name][ext]");
          },
        },
        { from: '**/*.{html,css}',context:'sample/' }
      ]
      // { from: 'src/vendor/bpmn-js/assets/**', to: 'dist/vendor/bpmn-propertyPanel/'},
      // { from: '**/*.{html,css}', context: 'sample/' }
    
  })
  ],
  mode: 'production',
  devtool: 'inline-source-map',
  devServer: {
  },
  stats: {
    errorDetails: true
  }
};