Fail build when Webpack produces warnings or errors (#1842)

* Fail build when WebPack produces errors and optionally on warnings

Fixes #1527

* Rework

* Added returns

plugins/plugin-webpack/README.md

@@ -57,6 +57,7 @@ The options object is optional.
 - `extendConfig: (config: WebpackConfig) => WebpackConfig` - extend your webpack config, see below.
 - `manifest: boolean | string` - Enable generating a manifest file. The default value is `false`, the default file name is `./asset-manifest.json` if setting manifest to `true`. The relative path is resolved from the output directory.
 - `htmlMinifierOptions: boolean | object` - [See below](#minify-html).
+- `failOnWarnings: boolean` - Does fail the build when Webpack emits warnings. The default value is `false`.
 
 #### Extending The Default Webpack Config
 

plugins/plugin-webpack/plugin.js

@@ -379,10 +379,18 @@ module.exports = function plugin(config, args = {}) {
             reject(err);
             return;
           }
+          const info = stats.toJson(extendedConfig.stats);
           if (stats.hasErrors()) {
-            const info = stats.toJson(extendedConfig.stats);
-            console.error(info.warnings.join('\n-----\n'));
-            console.error(info.errors.join('\n-----\n'));
+            console.error('Webpack errors:\n' + info.errors.join('\n-----\n'));
+            reject(Error(`Webpack failed with ${info.errors} error(s).`));
+            return;
+          }
+          if (stats.hasWarnings()) {
+            console.error('Webpack warnings:\n' + info.warnings.join('\n-----\n'));
+            if (args.failOnWarnings) {
+              reject(Error(`Webpack failed with ${info.warnings} warnings(s).`));
+              return;
+            }
           }
           resolve(stats);
         });