allow extending webpack config

Author: KurtGokhan

Diff for: config/paths.js

@@ -73,6 +73,7 @@ module.exports = {
   yarnLockFile: resolveApp('yarn.lock'),
   testsSetup: resolveModule(resolveApp, 'src/setupTests'),
   proxySetup: resolveApp('src/setupProxy.js'),
+  webpackSetup: resolveApp('webpack.config.js'),
   appNodeModules: resolveApp('node_modules'),
   appWebpackCache: resolveApp('node_modules/.cache'),
   appTsBuildInfoFile: resolveApp('node_modules/.cache/tsconfig.tsbuildinfo'),
@@ -98,6 +99,7 @@ module.exports = {
   yarnLockFile: resolveApp('yarn.lock'),
   testsSetup: resolveModule(resolveApp, 'src/setupTests'),
   proxySetup: resolveApp('src/setupProxy.js'),
+  webpackSetup: resolveApp('webpack.config.js'),
   appNodeModules: resolveApp('node_modules'),
   appWebpackCache: resolveApp('node_modules/.cache'),
   appTsBuildInfoFile: resolveApp('node_modules/.cache/tsconfig.tsbuildinfo'),
@@ -136,6 +138,7 @@ if (
     yarnLockFile: resolveOwn(`${templatePath}/yarn.lock`),
     testsSetup: resolveModule(resolveOwn, `${templatePath}/src/setupTests`),
     proxySetup: resolveOwn(`${templatePath}/src/setupProxy.js`),
+    webpackSetup: resolveApp(`${templatePath}/webpack.config.js`),
     appNodeModules: resolveOwn('node_modules'),
     appWebpackCache: resolveOwn('node_modules/.cache'),
     appTsBuildInfoFile: resolveOwn('node_modules/.cache/tsconfig.tsbuildinfo'),

Diff for: config/webpack.config.js

@@ -82,7 +82,7 @@ const sassModuleRegex = /\.module\.(scss|sass)$/;
 
 // This is the production and development configuration.
 // It is focused on developer experience, fast rebuilds, and a minimal bundle.
-module.exports = function (webpackEnv) {
+const baseConfigFactory = function (webpackEnv) {
   const isEnvDevelopment = webpackEnv === 'development';
   const isEnvProduction = webpackEnv === 'production';
   const shouldExtractCss = isEnvProduction && extractCss;
@@ -650,3 +650,19 @@ module.exports = function (webpackEnv) {
     performance: false,
   };
 };
+
+module.exports = function (webpackEnv) {
+  const baseConfig = baseConfigFactory(webpackEnv);
+
+  if (fs.existsSync(paths.webpackSetup)) {
+    const customSetup = require(paths.webpackSetup);
+
+    if (typeof customSetup !== 'function') {
+      throw new Error('Custom webpack config file must export a function that accepts `env` as first parameter and `defaultConfig` as second');
+    }
+
+    return customSetup(webpackEnv, baseConfig);
+  }
+
+  return baseConfig;
+};