feat(webpack): extendable `babel.presets` and babel `envName` (#5637)

packages/webpack/src/config/base.js

@@ -1,7 +1,6 @@
 import path from 'path'
 import consola from 'consola'
 import TimeFixPlugin from 'time-fix-plugin'
-import clone from 'lodash/clone'
 import cloneDeep from 'lodash/cloneDeep'
 import escapeRegExp from 'lodash/escapeRegExp'
 import VueLoader from 'vue-loader'
@@ -70,21 +69,28 @@ export default class WebpackBaseConfig {
   }
 
   getBabelOptions() {
-    const options = clone(this.buildContext.buildOptions.babel)
-
-    if (typeof options.presets === 'function') {
-      options.presets = options.presets({ isServer: this.isServer })
+    const options = {
+      ...this.buildContext.buildOptions.babel,
+      envName: this.name
     }
 
-    if (!options.babelrc && !options.presets) {
-      options.presets = [
-        [
+    if (options.configFile !== false) {
+      return options
+    }
+
+    const defaultPreset = [
       require.resolve('@nuxt/babel-preset-app'),
       {
         buildTarget: this.isServer ? 'server' : 'client'
       }
     ]
-      ]
+
+    if (typeof options.presets === 'function') {
+      options.presets = options.presets({ isServer: this.isServer }, defaultPreset)
+    }
+
+    if (!options.babelrc && !options.presets) {
+      options.presets = [ defaultPreset ]
     }
 
     return options

packages/webpack/src/config/modern.js

@@ -1,4 +1,3 @@
-import clone from 'lodash/clone'
 import WebpackClientConfig from './client'
 
 export default class WebpackModernConfig extends WebpackClientConfig {
@@ -15,9 +14,10 @@ export default class WebpackModernConfig extends WebpackClientConfig {
   }
 
   getBabelOptions() {
-    const options = clone(this.buildContext.buildOptions.babel)
-
-    options.presets = [
+    return {
+      ...this.buildContext.buildOptions.babel,
+      envName: this.name,
+      presets: [
         [
           require.resolve('@nuxt/babel-preset-app'),
           {
@@ -25,7 +25,6 @@ export default class WebpackModernConfig extends WebpackClientConfig {
           }
         ]
       ]
-
-    return options
+    }
   }
 }