fix: allow for deep nested webpack options

lib/KarmaWebpackController.js

@@ -5,6 +5,7 @@ const fs = require('fs');
 const os = require('os');
 
 const webpack = require('webpack');
+const merge = require('merge');
 
 class KarmaSyncPlugin {
   constructor(options) {
@@ -64,6 +65,7 @@ const defaultWebpackOptions = {
       },
     },
   },
+  plugins: [],
   // Something like this will be auto added by this.configure()
   // entry: {
   //   'foo-one.test.js': 'path/to/test/foo-one.test.js',
@@ -75,36 +77,54 @@ const defaultWebpackOptions = {
 };
 
 class KarmaWebpackController {
-  constructor() {
-    this.isActive = false;
-    this.bundlesContent = {};
-    this.__debounce = false;
+  set webpackOptions(options) {
+    this.__webpackOptions = options;
   }
 
-  configure(webpackOptions, karmaOptions) {
-    this.__webpackOptions = {
-      ...defaultWebpackOptions,
-      ...webpackOptions,
-    };
+  get webpackOptions() {
+    return this.__webpackOptions;
+  }
+
+  set karmaEmitter(emitter) {
+    this.__karmaEmitter = emitter;
 
     this.__webpackOptions.plugins = this.__webpackOptions.plugins || [];
     this.__webpackOptions.plugins.push(
       new KarmaSyncPlugin({
-        karmaEmitter: karmaOptions.emitter,
+        karmaEmitter: emitter,
         controller: this,
       })
     );
 
-    karmaOptions.emitter.on('exit', (done) => {
+    emitter.on('exit', (done) => {
       this.onKarmaExit();
       done();
     });
   }
 
+  get karmaEmitter() {
+    return this.__karmaEmitter;
+  }
+
   get outputPath() {
     return this.__webpackOptions.output.path;
   }
 
+  constructor() {
+    this.isActive = false;
+    this.bundlesContent = {};
+    this.__debounce = false;
+    this.__webpackOptions = defaultWebpackOptions;
+  }
+
+  updateWebpackOptions(newOptions) {
+    this.__webpackOptions = merge.recursive(
+      true,
+      this.__webpackOptions,
+      newOptions
+    );
+  }
+
   async bundle() {
     if (this.isActive === false && this.__debounce === false) {
       console.log('Webpack bundling...');
@@ -161,4 +181,8 @@ class KarmaWebpackController {
   }
 }
 
-module.exports = KarmaWebpackController;
+module.exports = {
+  KarmaSyncPlugin,
+  KarmaWebpackController,
+  defaultWebpackOptions,
+};

lib/karma-webpack.js

@@ -3,7 +3,7 @@ const fs = require('fs');
 
 const glob = require('glob');
 
-const KarmaWebpackController = require('./KarmaWebpackController');
+const { KarmaWebpackController } = require('./KarmaWebpackController');
 
 const controller = new KarmaWebpackController();
 
@@ -57,15 +57,12 @@ function preprocessorsToWebpackEntries(preprocessors) {
 function preprocessorFactory(config, emitter) {
   // one time setup
   if (controller.isActive === false) {
-    controller.configure(
-      {
-        entry: preprocessorsToWebpackEntries(config.preprocessors),
-        watch: config.autoWatch,
-      },
-      {
-        emitter,
-      }
-    );
+    controller.updateWebpackOptions({
+      entry: preprocessorsToWebpackEntries(config.preprocessors),
+      watch: config.autoWatch,
+    });
+    controller.updateWebpackOptions(config.webpack);
+    controller.karmaEmitter = emitter;
   }
 
   return async function processFile(content, file, done) {

package.json

@@ -36,7 +36,8 @@
     "webpack": "^4.0.0"
   },
   "dependencies": {
-    "glob": "^7.1.3"
+    "glob": "^7.1.3",
+    "merge": "^1.2.1"
   },
   "devDependencies": {
     "@commitlint/cli": "^7.1.1",

test/KarmaWebpackController.test.js

@@ -0,0 +1,26 @@
+const {
+  KarmaWebpackController,
+  defaultWebpackOptions,
+} = require('../lib/KarmaWebpackController');
+
+describe('KarmaWebpackController', () => {
+  it('applies the default webpackOptions', () => {
+    const controller = new KarmaWebpackController();
+    expect(controller.webpackOptions).toEqual(defaultWebpackOptions);
+  });
+
+  it('can provide custom nested webpackOptions', () => {
+    const controller = new KarmaWebpackController();
+    controller.updateWebpackOptions({
+      output: {
+        path: 'foo',
+        publicPath: 'bar',
+      },
+    });
+    expect(controller.webpackOptions.output.path).toBe('foo');
+    expect(controller.webpackOptions.output.publicPath).toBe('bar');
+    expect(controller.webpackOptions.output.filename).toBe(
+      defaultWebpackOptions.output.filename
+    );
+  });
+});