webpack.js

const path = require('path');
const webpack = require('webpack');
const FriendlyErrorsWebpackPlugin = require('friendly-errors-webpack-plugin');
const { toGlobalName, externals } = require('./externals');
const pkg = require(path.join(process.cwd(), 'package.json'));

const isProduction = process.env.NODE_ENV === 'production';

const rules = () => ({
  js: () => ({
    test: /\.js$/,
    exclude: /node_modules/,
    use: {
      loader: 'babel-loader',
      options: {
        rootMode: 'upward',
        // configFile: path.resolve(`${__dirname}/../babel.config.js`),
      },
    },
  }),
  css: () => ({
    test: /\.css$/,
    include: [/(ol|redux-notifications|react-datetime)/],
    use: ['to-string-loader', 'css-loader'],
  }),
  svg: () => ({
    test: /\.svg(\?v=\d+\.\d+\.\d+)?$/,
    exclude: [/node_modules/],
    use: 'svg-inline-loader',
  }),
});

const plugins = () => {
  return {
    ignoreEsprima: () => new webpack.IgnorePlugin(/^esprima$/, /js-yaml/),
    ignoreMomentOptionalDeps: () => new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
    friendlyErrors: () => new FriendlyErrorsWebpackPlugin(),
  };
};

const stats = () => {
  if (isProduction) {
    return {
      builtAt: false,
      chunks: false,
      colors: true,
      entrypoints: false,
      errorDetails: false,
      hash: false,
      modules: false,
      timings: false,
      version: false,
      warnings: false,
    };
  }
  return {
    all: false,
  };
};

const umdPath = path.resolve(process.cwd(), 'dist');
const umdDirPath = path.resolve(process.cwd(), 'dist/umd');
const cjsPath = path.resolve(process.cwd(), 'dist/cjs');
const targetOutputs = () => {
  console.log(`Building [${pkg.name}, library: ${toGlobalName(pkg.name)}]`);
  return {
    umd: {
      path: umdPath,
      filename: `${pkg.name}.js`,
      library: toGlobalName(pkg.name),
      libraryTarget: 'umd',
      libraryExport: toGlobalName(pkg.name),
      umdNamedDefine: true,
      globalObject: 'window',
    },
    umddir: {
      path: umdDirPath,
      filename: `index.js`,
      library: toGlobalName(pkg.name),
      libraryTarget: 'umd',
      libraryExport: toGlobalName(pkg.name),
      umdNamedDefine: true,
      globalObject: 'window',
    },
    cjs: {
      path: cjsPath,
      filename: 'index.js',
      library: toGlobalName(pkg.name),
      libraryTarget: 'window',
    },
  };
};

const umdExternals = Object.keys(pkg.peerDependencies || {}).reduce((previous, key) => {
  if (!externals[key]) throw `Missing external [${key}]`;
  previous[key] = externals[key] || null;
  return previous;
}, {});

/**
 * Use [getConfig({ target:'umd' }), getConfig({ target:'cjs' })] for
 *  getting multiple configs and add the new output in targetOutputs if needed.
 * Default: umd
 */
const baseConfig = ({ target = isProduction ? 'umd' : 'umddir' } = {}) => ({
  context: process.cwd(),
  mode: isProduction ? 'production' : 'development',
  entry: './src/index.js',
  output: targetOutputs()[target],
  module: {
    rules: Object.values(rules()).map(rule => rule()),
  },
  plugins: Object.values(plugins()).map(plugin => plugin()),
  devtool: 'source-map',
  target: 'web',

  /**
   * Exclude peer dependencies from package bundles.
   */
  externals:
    target.substr(0, 3) === 'umd'
      ? umdExternals
      : (context, request, cb) => {
          const externals = Object.keys(pkg.peerDependencies || {});
          const isPeerDep = dep => new RegExp(`^${dep}($|/)`).test(request);
          return externals.some(isPeerDep) ? cb(null, request) : cb();
        },
  stats: stats(),
});

const getConfig = ({ baseOnly = false } = {}) => {
  if (baseOnly) {
    // netlify-cms build
    return baseConfig({ target: 'umd' });
  }
  return [baseConfig({ target: 'umd' })];
};

module.exports = {
  getConfig,
  rules: rules(),
  plugins: plugins(),
};