simplify _children & _childCtor

Author: yyx990803

src/api/child.js

@@ -21,9 +21,6 @@ exports.$addChild = function (opts, BaseCtor) {
     : BaseCtor.options.inherit
   if (inherit) {
     var ctors = parent._childCtors
-    if (!ctors) {
-      ctors = parent._childCtors = {}
-    }
     ChildVue = ctors[BaseCtor.cid]
     if (!ChildVue) {
       var optionName = BaseCtor.options.name
@@ -45,9 +42,6 @@ exports.$addChild = function (opts, BaseCtor) {
   opts._parent = parent
   opts._root = parent.$root
   var child = new ChildVue(opts)
-  if (!this._children) {
-    this._children = []
-  }
   this._children.push(child)
   return child
 }

src/api/events.js

@@ -122,13 +122,11 @@ exports.$broadcast = function (event) {
   // then there's no need to broadcast.
   if (!this._eventsCount[event]) return
   var children = this._children
-  if (children) {
-    for (var i = 0, l = children.length; i < l; i++) {
-      var child = children[i]
-      child.$emit.apply(child, arguments)
-      if (!child._eventCancelled) {
-        child.$broadcast.apply(child, arguments)
-      }
+  for (var i = 0, l = children.length; i < l; i++) {
+    var child = children[i]
+    child.$emit.apply(child, arguments)
+    if (!child._eventCancelled) {
+      child.$broadcast.apply(child, arguments)
     }
   }
   return this

src/directives/if.js

@@ -53,17 +53,13 @@ module.exports = {
   compile: function (template) {
     var vm = this.vm
     var frag = templateParser.clone(template)
-    var originalChildLength = vm._children
-      ? vm._children.length
-      : 0
+    var originalChildLength = vm._children.length
     this.unlink = this.linker
       ? this.linker(vm, frag)
       : vm.$compile(frag)
     transition.blockAppend(frag, this.end, vm)
-    this.children = vm._children
-      ? vm._children.slice(originalChildLength)
-      : null
-    if (this.children && _.inDoc(vm.$el)) {
+    this.children = vm._children.slice(originalChildLength)
+    if (this.children.length && _.inDoc(vm.$el)) {
       this.children.forEach(function (child) {
         child._callHook('attached')
       })

src/instance/compile.js

@@ -122,11 +122,9 @@ exports._destroy = function (remove, deferCleanup) {
     parent._children.splice(i, 1)
   }
   // destroy all children.
-  if (this._children) {
-    i = this._children.length
-    while (i--) {
-      this._children[i].$destroy()
-    }
+  i = this._children.length
+  while (i--) {
+    this._children[i].$destroy()
   }
   // teardown parent linkers
   if (this._containerUnlinkFn) {

src/instance/events.js

@@ -80,7 +80,6 @@ exports._initDOMHooks = function () {
 function onAttached () {
   this._isAttached = true
   var children = this._children
-  if (!children) return
   for (var i = 0, l = children.length; i < l; i++) {
     var child = children[i]
     if (!child._isAttached && inDoc(child.$el)) {
@@ -96,7 +95,6 @@ function onAttached () {
 function onDetached () {
   this._isAttached = false
   var children = this._children
-  if (!children) return
   for (var i = 0, l = children.length; i < l; i++) {
     var child = children[i]
     if (child._isAttached && !inDoc(child.$el)) {

src/instance/init.js

@@ -46,9 +46,8 @@ exports._init = function (options) {
   this._isBeingDestroyed = false
 
   // children
-  this._children =         // @type {Array}
-  this._childCtors = null  // @type {Object} - hash to cache
-                           // child constructors
+  this._children = []
+  this._childCtors = {}
 
   // merge options.
   options = this.$options = mergeOptions(

src/instance/scope.js

@@ -117,14 +117,11 @@ exports._digest = function () {
     this._watcherList[i].update()
   }
   var children = this._children
-  var child
-  if (children) {
-    i = children.length
-    while (i--) {
-      child = children[i]
-      if (child.$options.inherit) {
-        child._digest()
-      }
+  i = children.length
+  while (i--) {
+    var child = children[i]
+    if (child.$options.inherit) {
+      child._digest()
     }
   }
 }

test/unit/specs/directives/component_spec.js

@@ -189,7 +189,7 @@ if (_.inBrowser) {
         }
       })
       expect(el.textContent).toBe('')
-      expect(vm._children).toBeNull()
+      expect(vm._children.length).toBe(0)
       expect(vm._directives.length).toBe(1) // v-if
       vm.ok = true
       _.nextTick(function () {

test/unit/specs/directives/if_spec.js

@@ -28,7 +28,7 @@ if (_.inBrowser) {
       })
       // lazy instantitation
       expect(el.innerHTML).toBe(wrap(''))
-      expect(vm._children).toBeNull()
+      expect(vm._children.length).toBe(0)
       vm.test = true
       _.nextTick(function () {
         expect(el.innerHTML).toBe(wrap('<div><div>A</div><!--v-component--></div>'))
@@ -91,7 +91,7 @@ if (_.inBrowser) {
       })
       vm.$appendTo(document.body)
       expect(el.innerHTML).toBe(wrap(''))
-      expect(vm._children).toBeNull()
+      expect(vm._children.length).toBe(0)
       vm.ok = true
       _.nextTick(function () {
         expect(el.innerHTML).toBe(wrap('<div>123</div><!--v-component-->'))
@@ -127,7 +127,7 @@ if (_.inBrowser) {
         }
       })
       expect(el.innerHTML).toBe(wrap(''))
-      expect(vm._children).toBeNull()
+      expect(vm._children.length).toBe(0)
       // toggle if with lazy instantiation
       vm.ok = true
       _.nextTick(function () {