webpack.config.js

'use strict';

const path = require('path');
const merge = require('webpack-merge');
const FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');

const parts = require('./webpack.parts');

const paths = {
	lib: path.join(__dirname, 'js'),
	build: path.join(__dirname, 'dist')
};

const lintJSOptions = {
	emitWarning: true,

	// Fail only on errors
	failOnWarning: false,
	failOnError: true,

	// Toggle autofix
	fix: true,

	formatter: require('eslint-friendly-formatter')
};

const commonConfig = merge([
	{
		devtool: 'source-map',
		entry: {
			bundle: paths.lib + '/PluginAPI.js'
		},
		output: {
			path: paths.build,
			library: 'PluginAPI',
			libraryTarget: 'umd'
		},
		externals: {
			jquery: 'jQuery',
			pm: 'pm'
		},
		plugins: [
			new CopyWebpackPlugin([{
				from: paths.lib + '/vendors/jquery.postmessage.js',
				to: 'jquery.postmessage.js'
			}]),
			new FriendlyErrorsPlugin()
		]
	},
	parts.lintJS({include: paths.lib, options: lintJSOptions}),
	parts.loadJS({include: paths.lib})
]);

const libraryConfig = merge([
	commonConfig,
	{
		mode: 'development',
		output: {
			filename: '[name].js'
		}
	}
]);

const libraryMinConfig = merge([
	commonConfig,
	{
		mode: 'production',
		output: {
			filename: '[name].min.js'
		}
	},
	parts.minifyJS({
		terserOptions: {
			parse: {
				// we want terser to parse ecma 8 code. However, we don't want it
				// to apply any minfication steps that turns valid ecma 5 code
				// into invalid ecma 5 code. This is why the 'compress' and 'output'
				// sections only apply transformations that are ecma 5 safe
				// https://github.com/facebook/create-react-app/pull/4234
				ecma: 8
			},
			compress: {
				ecma: 5,
				warnings: false,
				// Disabled because of an issue with Uglify breaking seemingly valid code:
				// https://github.com/facebook/create-react-app/issues/2376
				// Pending further investigation:
				// https://github.com/mishoo/UglifyJS2/issues/2011
				comparisons: false
			},
			mangle: {
				safari10: true
			},
			output: {
				ecma: 5,
				comments: false,
				// Turned on because emoji and regex is not minified properly using default
				// https://github.com/facebook/create-react-app/issues/2488
				ascii_only: true
			}
		},
		// Use multi-process parallel running to improve the build speed
		// Default number of concurrent runs: os.cpus().length - 1
		parallel: true,
		// Enable file caching
		cache: true,
		sourceMap: true
	})
]);

module.exports = (env) => (
	env === 'production' ? [libraryMinConfig, libraryConfig] : libraryConfig
);