core/build/webpack.base.conf.js

const path = require('path');

function resolve(dir) {
  return path.join(__dirname, '..', dir)
}

module.exports = {
  context: resolve('src'),
  entry: './index.ts',
  plugins: [],
  externals: ['lodash', 'd3'],
  module: {
    rules: [
      {
        test: /\.ts$/,
        use: 'ts-loader',
        exclude: /node_modules/
      },
      {
        test: /\.css$/,
        use: [
          { loader: 'style-loader', options: { injectType: 'lazyStyleTag' } },
          'css-loader',
        ],
        exclude: /node_modules/
      }
    ],
  },
  resolve: {
    extensions: ['.ts', '.js'],
  },
  output: {
    filename: 'index.js',
    path: resolve('dist'),
    libraryTarget: 'umd',
    umdNamedDefine: true
  }
};