webpack.config.test.js

const nodeExternals = require('webpack-node-externals');
const path = require('path');

const ProvidePlugin = require('webpack').ProvidePlugin;

module.exports = (env, argv) => {

    const isDebug = env == 'dbg';
    const loaders = [];

    if (!isDebug) {
        loaders.push('istanbul-instrumenter-loader');
    }

    loaders.push('ts-loader');

    return {
        mode: 'development',
        entry: './src/index.ts',
        resolve: {
            extensions: ['.ts'],
        },
        module: {
            rules: [{
                test: /\.ts$/,
                exclude: /node_modules/,
                include: path.resolve('src'), // instrument only testing sources with Istanbul, after ts-loader runs
                use: loaders
            }],
        },
        plugins: [
          new ProvidePlugin({
            'TextDecoder': ['text-encoding', 'TextDecoder'],
            'TextEncoder': ['text-encoding', 'TextEncoder'],
          })
        ],
        target: 'node',  // webpack should compile node compatible code
        externals: [nodeExternals()], // in order to ignore all modules in node_modules folder
        devtool: 'inline-cheap-module-source-map'
    };
};