re-implement nextTick with MutationObserver

yyx990803 · yyx990803 · commit 933d4c4477b6 · 2014-12-07T22:11:02.000-05:00
diff --git a/.jshintrc b/.jshintrc
@@ -14,6 +14,7 @@
   "proto": true,
   "globals": {
     "console": true,
-    "DocumentFragment": true
+    "DocumentFragment": true,
+    "WebkitMutationObserver": true
   }
 }
diff --git a/src/util/env.js b/src/util/env.js
@@ -24,11 +24,43 @@ var inBrowser = exports.inBrowser =
  * @param {Object} ctx
  */
 
-var defer = inBrowser
-  ? (window.requestAnimationFrame ||
-    window.webkitRequestAnimationFrame ||
-    setTimeout)
-  : setTimeout
+var defer
+/* istanbul ignore if */
+if (typeof MutationObserver !== 'undefined') {
+  defer = deferFromMutationObserver(MutationObserver)
+} else
+/* istanbul ignore if */
+if (typeof WebkitMutationObserver !== 'undefined') {
+  defer = deferFromMutationObserver(WebkitMutationObserver)
+} else
+/* istanbul ignore if */
+if (typeof setImmediate !== 'undefined') {
+  defer = setImmediate
+} else {
+  defer = inBrowser
+    ? (window.requestAnimationFrame ||
+      window.webkitRequestAnimationFrame ||
+      setTimeout)
+    : setTimeout
+}
+
+/* istanbul ignore next */
+function deferFromMutationObserver (Observer) {
+  var queue = []
+  var node = document.createTextNode('0')
+  var i = 0
+  new Observer(function () {
+    var l = queue.length
+    for (var i = 0; i < l; i++) {
+      queue[i]()
+    }
+    queue = queue.slice(l)
+  }).observe(node, { characterData: true })
+  return function mutationObserverDefer (cb) {
+    queue.push(cb)
+    node.nodeValue = (i = ++i % 2)
+  }
+}
 
 exports.nextTick = function (cb, ctx) {
   if (ctx) {
diff --git a/test/unit/specs/directives/style_spec.js b/test/unit/specs/directives/style_spec.js
@@ -57,6 +57,12 @@ if (_.inBrowser) {
       expect(el.style.color).toBe('')
     })
 
+    it('ignore unsupported property', function () {
+      dir.arg = 'unsupported'
+      dir.update('test')
+      expect(el.style.unsupported).not.toBe('test')
+    })
+
     it('auto prefixing', function () {
       var prop = checkPrefixedProp('transform')
       dir.arg = 'transform'
diff --git a/test/unit/specs/transition/transition_spec.js b/test/unit/specs/transition/transition_spec.js
@@ -210,10 +210,10 @@ if (_.inBrowser && !_.isIE9) {
         el.__v_trans.id = 'test'
         // cascaded class style
         el.classList.add('test')
-        // wait a tick before applying the transition
+        // wait a frame before applying the transition
         // because doing so in the same frame won't trigger
         // transition
-        _.nextTick(function () {
+        setTimeout(function () {
           transition.apply(el, -1, op, vm, cb)
           _.nextTick(function () {
             expect(op).not.toHaveBeenCalled()
@@ -226,7 +226,7 @@ if (_.inBrowser && !_.isIE9) {
               done()
             })
           })
-        })
+        }, 0)
       })
 
       it('animation enter', function (done) {

Original file line number	Diff line number	Diff line change
`@@ -14,6 +14,7 @@`
`14`	`14`	`"proto": true,`
`15`	`15`	`"globals": {`
`16`	`16`	`"console": true,`
`17`		`- "DocumentFragment": true`
	`17`	`+ "DocumentFragment": true,`
	`18`	`+ "WebkitMutationObserver": true`
`18`	`19`	`}`
`19`	`20`	`}`