Give this to data()

lib/app/client.js

@@ -3,7 +3,7 @@
 import Vue from 'vue'
 import middleware from './middleware'
 import { app, router<%= (store ? ', store' : '') %>, NuxtError } from './index'
-import { getMatchedComponents, getMatchedComponentsInstances, flatMapComponents, getContext, promiseSeries, promisify, getLocation, compile } from './utils'
+import { applyAsyncData, getMatchedComponents, getMatchedComponentsInstances, flatMapComponents, getContext, promiseSeries, promisify, getLocation, compile } from './utils'
 const noopData = () => { return {} }
 const noopFetch = () => {}
 let _lastPaths = []
@@ -148,18 +148,7 @@ function render (to, from, next) {
       if (Component.options.asyncData && typeof Component.options.asyncData === 'function') {
         var promise = promisify(Component.options.asyncData, context)
         promise.then((asyncDataResult) => {
-          let data = {}
-          // Call data() if defined
-          if (Component.options.data && typeof Component.options.data === 'function') {
-            data = Component.options.data()
-          }
-          // Merge data() and asyncData() results
-          data = Object.assign(data, asyncDataResult)
-          // Overwrite .data() method with merged data
-          Component.options.data = () => data
-          if (Component._Ctor && Component._Ctor.options) {
-            Component._Ctor.options.data = Component.options.data
-          }
+          applyAsyncData(Component, asyncDataResult)
           <%= (loading ? 'this.$loading.increase && this.$loading.increase(30)' : '') %>
         })
         promises.push(promise)
@@ -218,7 +207,7 @@ function fixPrepatch (to, ___) {
     _lastComponentsFiles = instances.map((instance, i) => {
       if (!instance) return '';
       if (_lastPaths[i] === instance.constructor._path && typeof instance.constructor.options.data === 'function') {
-        let newData = instance.constructor.options.data()
+        let newData = instance.constructor.options.data.call(instance)
         for (let key in newData) {
           Vue.set(instance.$data, key, newData[key])
         }
@@ -305,13 +294,10 @@ function addHotReload ($component, depth) {
       return callMiddleware.call(this, Components, context, this.layout)
     })
     .then(() => {
-      // Call asyncData()
+      // Call asyncData(context)
       let pAsyncData = promisify(Component.options.asyncData || noopData, context)
       pAsyncData.then((asyncDataResult) => {
-        let data = (typeof Component.options.data === 'function' ? Component.options.data() : noopData())
-        data = Object.assign(data, asyncDataResult)
-        Component.options.data = () => data
-        Component._Ctor.options.data = Component.options.data
+        applyAsyncData(Component, asyncDataResult)
         <%= (loading ? 'this.$loading.increase && this.$loading.increase(30)' : '') %>
       })
       promises.push(pAsyncData)
@@ -350,16 +336,7 @@ const resolveComponents = flatMapComponents(router.match(path), (Component, _, m
           Component.extendOptions = Component.options
         }
         if (NUXT.serverRendered) {
-          let data = {}
-          if (Component.options.data && typeof Component.options.data === 'function') {
-            data = Component.options.data()
-          }
-          // Merge data() and asyncData() results
-          data = Object.assign(data, NUXT.data[index])
-          Component.options.data = () => data
-          if (Component._Ctor && Component._Ctor.options) {
-            Component._Ctor.options.data = Component.options.data
-          }
+          applyAsyncData(Component, NUXT.data[index])
         }
         match.components[key] = Component
         resolve(Component)

lib/app/server.js

@@ -8,7 +8,7 @@ import { stringify } from 'querystring'
 import { omit } from 'lodash'
 import middleware from './middleware'
 import { app, router<%= (store ? ', store' : '') %>, NuxtError } from './index'
-import { getMatchedComponents, getContext, promiseSeries, promisify, urlJoin } from './utils'
+import { applyAsyncData, getMatchedComponents, getContext, promiseSeries, promisify, urlJoin } from './utils'
 
 const isDev = <%= isDev %>
 const _app = new Vue(app)
@@ -172,15 +172,8 @@ export default context => {
         let promise = promisify(Component.options.asyncData, ctx)
         // Call asyncData(context)
         promise.then((asyncDataResult) => {
-          let data = {}
-          // Call data() if defined
-          if (Component.options.data && typeof Component.options.data === 'function') {
-            data = Component.options.data()
-          }
-          // Merge data() and asyncData() results
-          data = Object.assign(data, asyncDataResult)
-          Component.options.data = () => data
-          Component._Ctor.options.data = Component.options.data
+          applyAsyncData(Component, asyncDataResult)
+          return asyncDataResult
         })
         promises.push(promise)
       } else {

lib/app/utils.js

@@ -1,6 +1,19 @@
 'use strict'
 import { app } from './index'
 
+const noopData = () => ({})
+
+export function applyAsyncData (Component, asyncData = {}) {
+  const ComponentData = Component.options.data || noopData
+  Component.options.data = function () {
+    const data =  ComponentData.call(this)
+    return { ...data, ...asyncData }
+  }
+  if (Component._Ctor && Component._Ctor.options) {
+    Component._Ctor.options.data = Component.options.data
+  }
+}
+
 export function getMatchedComponents (route) {
   return [].concat.apply([], route.matched.map(function (m) {
     return Object.keys(m.components).map(function (key) {