Fix: A build should't break when assetsDir is an array (styleguidist#1367)

copy-webpack-plugin is not allowed `from` to be as an array. If we still want to use `from` and support array format for assetsDir, then we should pass array of objects `{from: ...}` to the plugin.

Closes styleguidist#1320

Author: mendrew

src/scripts/__tests__/make-webpack-config.spec.js

@@ -114,6 +114,11 @@ it('should set from with assetsDir in CopyWebpackPlugin', () => {
 	expect(CopyWebpackPlugin).toHaveBeenCalledWith([{ from: '/assets/' }]); //([
 });
 
+it('should set array of from with assetsDir array in CopyWebpackPlugin', () => {
+	makeWebpackConfig({ ...styleguideConfig, assetsDir: ['/assets1/', '/assets2/'] }, 'production');
+	expect(CopyWebpackPlugin).toHaveBeenCalledWith([{ from: '/assets1/' }, { from: '/assets2/' }]);
+});
+
 it('should add CopyWebpackPlugin to plugins in production', () => {
 	makeWebpackConfig({ ...styleguideConfig }, 'production');
 	expect(CopyWebpackPlugin).toHaveBeenCalledWith([]);

src/scripts/make-webpack-config.js

@@ -1,4 +1,5 @@
 const path = require('path');
+const castArray = require('lodash/castArray');
 const webpack = require('webpack');
 const TerserPlugin = require('terser-webpack-plugin');
 const MiniHtmlWebpackPlugin = require('mini-html-webpack-plugin');
@@ -92,13 +93,7 @@ module.exports = function(config, env) {
 					verbose: config.verbose === true,
 				}),
 				new CopyWebpackPlugin(
-					config.assetsDir
-						? [
-								{
-									from: config.assetsDir,
-								},
-						  ]
-						: []
+					config.assetsDir ? castArray(config.assetsDir).map(dir => ({ from: dir })) : []
 				),
 			],
 			optimization: {