make owner vm the context for js transition hooks

Author: yyx990803

src/transition/index.js

@@ -131,6 +131,7 @@ var apply = exports.apply = function (el, direction, op, vm, cb) {
       op,
       transData,
       jsTransition,
+      vm,
       cb
     )
   } else if (_.transitionEndEvent) {

src/transition/js.js

@@ -6,21 +6,22 @@
  * @param {Function} op - the actual DOM operation
  * @param {Object} data - target element's transition data
  * @param {Object} def - transition definition object
+ * @param {Vue} vm - the owner vm of the element
  * @param {Function} [cb]
  */
 
-module.exports = function (el, direction, op, data, def, cb) {
+module.exports = function (el, direction, op, data, def, vm, cb) {
   if (data.cancel) {
     data.cancel()
     data.cancel = null
   }
   if (direction > 0) { // enter
     if (def.beforeEnter) {
-      def.beforeEnter(el)
+      def.beforeEnter.call(vm, el)
     }
     op()
     if (def.enter) {
-      data.cancel = def.enter(el, function () {
+      data.cancel = def.enter.call(vm, el, function () {
         data.cancel = null
         if (cb) cb()
       })
@@ -29,7 +30,7 @@ module.exports = function (el, direction, op, data, def, cb) {
     }
   } else { // leave
     if (def.leave) {
-      data.cancel = def.leave(el, function () {
+      data.cancel = def.leave.call(vm, el, function () {
         data.cancel = null
         op()
         if (cb) cb()

test/unit/specs/transition_spec.js

@@ -327,9 +327,12 @@ if (_.inBrowser && !_.isIE9) {
       })
 
       it('beforeEnter', function () {
-        def.beforeEnter = jasmine.createSpy('js transition beforeEnter')
+        var spy = jasmine.createSpy('js transition beforeEnter')
+        def.beforeEnter = function (el) {
+          spy(this, el)
+        }
         transition.apply(el, 1, op, vm, cb)
-        expect(def.beforeEnter).toHaveBeenCalledWith(el)
+        expect(spy).toHaveBeenCalledWith(vm, el)
       })
 
       it('enter', function () {
@@ -339,10 +342,10 @@ if (_.inBrowser && !_.isIE9) {
           expect(op).toHaveBeenCalled()
           done()
           expect(cb).toHaveBeenCalled()
-          spy()
+          spy(this)
         }
         transition.apply(el, 1, op, vm, cb)
-        expect(spy).toHaveBeenCalled()
+        expect(spy).toHaveBeenCalledWith(vm)
       })
 
       it('leave', function () {
@@ -352,10 +355,10 @@ if (_.inBrowser && !_.isIE9) {
           done()
           expect(op).toHaveBeenCalled()
           expect(cb).toHaveBeenCalled()
-          spy()
+          spy(this)
         }
         transition.apply(el, -1, op, vm, cb)
-        expect(spy).toHaveBeenCalled()
+        expect(spy).toHaveBeenCalledWith(vm)
       })
 
       it('no def', function () {