webpack.config.js

const path = require('path')

const babelConfig = {
    presets: [
        [
            '@babel/env',
            {
                modules: false,
                useBuiltIns: 'usage',
                corejs: 3,
            }
        ]
    ],
    plugins: [
        '@babel/plugin-proposal-export-default-from',
        '@babel/plugin-proposal-export-namespace-from', ['@babel/plugin-transform-runtime', {
            helpers: true,
            regenerator: true,
            useESModules: true,
        }]
    ]
}

module.exports = {
    entry: './src/index.ts',
    resolve: {
        mainFields: ['module', 'browser', 'main'],
        modules: [
            'youchain.js/packages',
            // only resolve from project root, preventing version conflict of
            // dependencies in different web3-* packages
            path.resolve(__dirname, 'node_modules')
        ],
    },
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'youchain.js',
        library: 'YOUChain',
        libraryTarget: 'var',
        libraryExport: 'default',
    },
    module: {
        rules: [{
            test: /\.m?js$/,
            exclude: /node_modules/,
            use: {
                loader: 'babel-loader',
                options: babelConfig,
            }
        }]
    }
}