diff --git a/lib/nuxt.js b/lib/nuxt.js
index 93ee1499cc..6a6fbed55c 100644
--- a/lib/nuxt.js
+++ b/lib/nuxt.js
@@ -11,9 +11,12 @@ import Server from './server'
 import Defaults from './defaults'
 
 export default class Nuxt extends Tapable {
-  constructor (options = {}) {
+  constructor (_options = {}) {
     super()
 
+    // Clone options to prevent unwanted side-effects
+    const options = Object.assign({}, _options)
+
     // Normalize options
     if (options.loading === true) {
       delete options.loading
diff --git a/test/with-config.test.js b/test/with-config.test.js
index 07c299f245..41fb678f42 100644
--- a/test/with-config.test.js
+++ b/test/with-config.test.js
@@ -111,4 +111,5 @@ test.after('Should be able to start Nuxt with build done', async t => {
   config.rootDir = rootDir
   config.dev = false
   nuxt = new Nuxt(config)
+  await nuxt.init()
 })