cleanup / DRY up code with lodash, update readme and add test to verify devtool is always set unless false

Author: brian-mann

README.md

@@ -93,7 +93,7 @@ Object of webpack options. Just `require` in the options from your `webpack.conf
 }
 ```
 
-Source maps are always enabled unless explicitly disabled by specifying `devtool: false` or `mode: "production"`.
+Source maps are **always enabled** unless explicitly disabled by specifying `devtool: false`.
 
 Webpack [mode](https://webpack.js.org/configuration/mode/) is set to `development` if not present. You can set `mode` to "development", "production" or "none".
 

index.ts

@@ -1,7 +1,7 @@
-import * as webpack from 'webpack'
 import * as Promise from 'bluebird'
 import * as events from 'events'
-
+import * as _ from 'lodash'
+import * as webpack from 'webpack'
 import { createDeferred } from './deferred'
 
 const path = require('path')
@@ -122,40 +122,45 @@ const preprocessor: WebpackPreprocessor = (options: PreprocessorOptions = {}): F
       return bundles[filePath]
     }
 
-    // user can override the default options
-    let webpackOptions: webpack.Configuration = options.webpackOptions || getDefaultWebpackOptions()
-    const watchOptions = options.watchOptions || {}
+    const defaultWebpackOptions = getDefaultWebpackOptions()
 
-    debug('webpackOptions: %o', webpackOptions)
-    debug('watchOptions: %o', watchOptions)
-
-    const entry = [filePath].concat(options.additionalEntries || [])
     // we're provided a default output path that lives alongside Cypress's
     // app data files so we don't have to worry about where to put the bundled
     // file on disk
     const outputPath = path.extname(file.outputPath) === '.js'
       ? file.outputPath
       : `${file.outputPath}.js`
 
-    // we need to set entry and output
-    webpackOptions = Object.assign(webpackOptions, {
+    const entry = [filePath].concat(options.additionalEntries || [])
+
+    const watchOptions = options.watchOptions || {}
+
+    // user can override the default options
+    const webpackOptions: webpack.Configuration = _
+    .chain(options.webpackOptions)
+    .defaultTo(defaultWebpackOptions)
+    .defaults({
+      mode: defaultWebpackOptions.mode,
+    })
+    .assign({
+      // we need to set entry and output
       entry,
       output: {
         path: path.dirname(outputPath),
         filename: path.basename(outputPath),
       },
     })
+    .tap((opts) => {
+      if (opts.devtool !== false) {
+        debug('setting devtool to inline-source-map')
 
-    if (webpackOptions.devtool !== false) {
-      debug('setting devtool to inline-source-map')
-      webpackOptions.devtool = 'inline-source-map'
-    }
-
-    if (!('mode' in webpackOptions)) {
-      debug('setting webpack mode to development')
-      webpackOptions.mode = 'development'
-    }
+        opts.devtool = 'inline-source-map'
+      }
+    })
+    .value() as any
 
+    debug('webpackOptions: %o', webpackOptions)
+    debug('watchOptions: %o', watchOptions)
     debug(`input: ${filePath}`)
     debug(`output: ${outputPath}`)
 
@@ -282,8 +287,7 @@ const preprocessor: WebpackPreprocessor = (options: PreprocessorOptions = {}): F
   }
 }
 
-// provide a clone of the default options, lazy-loading them
-// so they aren't required unless the user utilizes them
+// provide a clone of the default options
 Object.defineProperty(preprocessor, 'defaultOptions', {
   get () {
     debug('get default options')

package.json

@@ -29,7 +29,8 @@
   },
   "dependencies": {
     "bluebird": "3.7.1",
-    "debug": "4.1.1"
+    "debug": "4.1.1",
+    "lodash": "4.17.15"
   },
   "devDependencies": {
     "@babel/core": "^7.0.1",

test/unit/index.spec.js

@@ -167,6 +167,14 @@ describe('webpack preprocessor', function () {
             })
           })
         })
+
+        it('always sets devtool even when mode is "production"', function () {
+          const options = { webpackOptions: { mode: 'production' } }
+
+          return this.run(options).then(() => {
+            expect(webpack).to.be.calledWithMatch({
+              devtool: 'inline-source-map',
+            })
           })
         })
       })
@@ -184,7 +192,9 @@ describe('webpack preprocessor', function () {
           const options = { webpackOptions: { mode: 'production' } }
 
           return this.run(options).then(() => {
-            expect(webpack.lastCall.args[0].mode).to.equal('production')
+            expect(webpack).to.be.calledWithMatch({
+              mode: 'production',
+            })
           })
         })
       })