webpack.config.js

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

module.exports = {
  context: __dirname,
  entry: slsw.lib.entries,
  target: 'node',
  mode: slsw.lib.webpack.isLocal ? 'development' : 'production',
  externalsPresets: { node: true }, // in order to ignore built-in modules like path, fs, etc.
  externals: [nodeExternals()], // in order to ignore all modules in node_modules folder
  devtool: 'source-map',
  resolve: {
    extensions: ['.mjs', '.json', '.ts'],
    symlinks: false,
    cacheWithContext: false,
  },
  module: {
    rules: [
      // all files with a `.ts` extension will be handled by `ts-loader`
      {
        test: /\.(ts?)$/,
        loader: 'ts-loader',
        exclude: [
          [
            path.resolve(__dirname, 'node_modules'),
            path.resolve(__dirname, '.serverless'),
            path.resolve(__dirname, '.webpack'),
          ],
        ],
        options: {
          transpileOnly: true,
          experimentalWatchApi: true,
        },
      },
      {
        test: /\.graphql$/,
        exclude: /node_modules/,
        loader: 'graphql-tag/loader',
      },
    ],
  },
  output: {
    libraryTarget: 'commonjs',
    path: path.join(__dirname, '.webpack'),
    filename: '[name].js',
    sourceMapFilename: '[file].map',
  },
};