Fix when functional component render method retrun null (fix vuejs#5536) (vuejs#5539)

gebilaoxiong · yyx990803 · commit 3b426efe60c3 · 2017-04-29T14:42:35.000+08:00
* fix:create empty vnode when functional component return null

* add test

* use isDef
diff --git a/src/core/vdom/create-element.js b/src/core/vdom/create-element.js
@@ -99,7 +99,7 @@ export function _createElement (
     // direct component options / constructor
     vnode = createComponent(tag, data, context, children)
   }
-  if (vnode !== undefined) {
+  if (isDef(vnode)) {
     if (ns) applyNS(vnode, ns)
     return vnode
   } else {
diff --git a/test/unit/features/options/functional.spec.js b/test/unit/features/options/functional.spec.js
@@ -1,4 +1,5 @@
 import Vue from 'vue'
+import { createEmptyVNode } from 'core/vdom/vnode'
 
 describe('Options functional', () => {
   it('should work', done => {
@@ -167,4 +168,21 @@ describe('Options functional', () => {
       vm.$destroy()
     }).then(done)
   })
+
+  it('create empty vnode when render return null', () => {
+    const child = {
+      functional: true,
+      render () {
+        return null
+      }
+    }
+    const vm = new Vue({
+      components: {
+        child
+      }
+    })
+    const h = vm.$createElement
+    const vnode = h('child')
+    expect(vnode).toEqual(createEmptyVNode())
+  })
 })

Original file line number	Diff line number	Diff line change
`@@ -99,7 +99,7 @@ export function _createElement (`
`99`	`99`	`// direct component options / constructor`
`100`	`100`	`vnode = createComponent(tag, data, context, children)`
`101`	`101`	`}`
`102`		`- if (vnode !== undefined) {`
	`102`	`+ if (isDef(vnode)) {`
`103`	`103`	`if (ns) applyNS(vnode, ns)`
`104`	`104`	`return vnode`
`105`	`105`	`} else {`