feat: implement "configureLoaderRule" method

Author: Kocal

lib/WebpackConfig.js

@@ -100,6 +100,9 @@ class WebpackConfig {
         this.eslintLoaderOptionsCallback = () => {};
         this.tsConfigurationCallback = () => {};
         this.handlebarsConfigurationCallback = () => {};
+        this.loaderConfigurationCallbacks = {
+            'eslint': () => {},
+        };
 
         // Plugins options
         this.cleanWebpackPluginPaths = ['**/*'];
@@ -716,6 +719,18 @@ class WebpackConfig {
         });
     }
 
+    configureLoaderRule(name, callback) {
+        if (!(name in this.loaderConfigurationCallbacks)) {
+            throw new Error(`Loader "${name}" is not configurable. Either open an issue or a pull request.`);
+        }
+
+        if (typeof callback !== 'function') {
+            throw new Error('Argument 2 to configureLoaderRule() must be a callback function.');
+        }
+
+        this.loaderConfigurationCallbacks[name] = callback;
+    }
+
     useDevServer() {
         return this.runtimeConfig.useDevServer;
     }

lib/config-generator.js

@@ -357,13 +357,13 @@ class ConfigGenerator {
         }
 
         if (this.webpackConfig.useEslintLoader) {
-            rules.push({
+            rules.push(applyOptionsCallback(this.webpackConfig.loaderConfigurationCallbacks['eslint'], {
                 test: /\.jsx?$/,
                 loader: 'eslint-loader',
                 exclude: /node_modules/,
                 enforce: 'pre',
                 options: eslintLoaderUtil.getOptions(this.webpackConfig)
-            });
+            }));
         }
 
         if (this.webpackConfig.useTypeScriptLoader) {