refactor: avoid using Object.assign in SSR code for basic renderer compat in other environments

src/platforms/web/entry-server-renderer.js

@@ -2,6 +2,7 @@
 
 process.env.VUE_ENV = 'server'
 
+import { extend } from 'shared/util'
 import modules from './server/modules/index'
 import baseDirectives from './server/directives/index'
 import { isUnaryTag, canBeLeftOpenTag } from './compiler/util'
@@ -13,13 +14,13 @@ export function createRenderer (options?: Object = {}): {
   renderToString: Function,
   renderToStream: Function
 } {
-  return _createRenderer(Object.assign({}, options, {
+  return _createRenderer(extend(extend({}, options), {
     isUnaryTag,
     canBeLeftOpenTag,
     modules,
     // user can provide server-side implementations for custom directives
     // when creating the renderer.
-    directives: Object.assign(baseDirectives, options.directives)
+    directives: extend(baseDirectives, options.directives)
   }))
 }
 

src/platforms/web/server/modules/attrs.js

@@ -4,7 +4,8 @@ import { escape } from '../util'
 
 import {
   isDef,
-  isUndef
+  isUndef,
+  extend
 } from 'shared/util'
 
 import {
@@ -22,7 +23,7 @@ export default function renderAttrs (node: VNodeWithData): string {
     let parent = node.parent
     while (isDef(parent)) {
       if (isDef(parent.data) && isDef(parent.data.attrs)) {
-        attrs = Object.assign({}, attrs, parent.data.attrs)
+        attrs = extend(extend({}, attrs), parent.data.attrs)
       }
       parent = parent.parent
     }

src/platforms/web/server/modules/dom-props.js

@@ -2,7 +2,7 @@
 
 import VNode from 'core/vdom/vnode'
 import { renderAttr } from './attrs'
-import { isDef, isUndef } from 'shared/util'
+import { isDef, isUndef, extend } from 'shared/util'
 import { propsToAttrMap, isRenderableAttr } from '../util'
 
 export default function renderDOMProps (node: VNodeWithData): string {
@@ -12,7 +12,7 @@ export default function renderDOMProps (node: VNodeWithData): string {
   let parent = node.parent
   while (isDef(parent)) {
     if (parent.data && parent.data.domProps) {
-      props = Object.assign({}, props, parent.data.domProps)
+      props = extend(extend({}, props), parent.data.domProps)
     }
     parent = parent.parent
   }

src/server/optimizing-compiler/runtime-helpers.js

@@ -23,7 +23,7 @@ export function installSSRHelpers (vm: Component) {
   while (Ctor.super) {
     Ctor = Ctor.super
   }
-  Object.assign(Ctor.prototype, {
+  extend(Ctor.prototype, {
     _ssrEscape: escape,
     _ssrNode: renderStringNode,
     _ssrList: renderStringList,

src/server/render.js

@@ -3,7 +3,8 @@
 import {
   isDef,
   isUndef,
-  isTrue
+  isTrue,
+  extend
 } from 'shared/util'
 
 import { escape } from 'web/server/util'
@@ -29,7 +30,7 @@ const normalizeRender = vm => {
   const { render, template, _scopeId } = vm.$options
   if (isUndef(render)) {
     if (template) {
-      Object.assign(vm.$options, ssrCompileToFunctions(template, {
+      extend(vm.$options, ssrCompileToFunctions(template, {
         scopeId: _scopeId
       }))
     } else {