无JIRA任务 更新fix.ie

dist/fix/fix.ie.js

@@ -166,55 +166,37 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
             }
         }
 
-        // Here we have async deferring wrappers using microtasks.
-        // In 2.5 we used (macro) tasks (in combination with microtasks).
-        // However, it has subtle problems when state is changed right before repaint
-        // (e.g. #6813, out-in transitions).
-        // Also, using (macro) tasks in event handler would cause some weird behaviors
-        // that cannot be circumvented (e.g. #7109, #7153, #7546, #7834, #8109).
-        // So we now use microtasks everywhere, again.
-        // A major drawback of this tradeoff is that there are some scenarios
-        // where microtasks have too high a priority and fire in between supposedly
-        // sequential events (e.g. #4521, #6690, which have workarounds)
-        // or even between bubbling of the same event (#6566).
-
-        // The nextTick behavior leverages the microtask queue, which can be accessed
-        // via either native Promise.then or MutationObserver.
-        // MutationObserver has wider support, however it is seriously bugged in
-        // UIWebView in iOS >= 9.3.3 when triggered in touch event handlers. It
-        // completely stops working after triggering a few times... so, if native
-        // Promise is available, we will use it:
-        /* istanbul ignore next, $flow-disable-line */
-        if (typeof Promise !== 'undefined' && isNative(Promise)) {
-            var p = Promise.resolve();
+        // An asynchronous deferring mechanism.
+        // In pre 2.4, we used to use microtasks (Promise/MutationObserver)
+        // but microtasks actually has too high a priority and fires in between
+        // supposedly sequential events (e.g. #4521, #6690) or even between
+        // bubbling of the same event (#6566). Technically setImmediate should be
+        // the ideal choice, but it's not available everywhere; and the only polyfill
+        // that consistently queues the callback after all DOM events triggered in the
+        // same loop is by using MessageChannel.
+        /* istanbul ignore if */
+        if (typeof setImmediate !== 'undefined' && isNative(setImmediate)) {
             timerFunc = function timerFunc() {
-                p.then(nextTickHandler);
+                setImmediate(nextTickHandler);
             };
-        } else if (!isIE && typeof MutationObserver !== 'undefined' && (isNative(MutationObserver) ||
-        // PhantomJS and iOS 7.x
-        MutationObserver.toString() === '[object MutationObserverConstructor]')) {
-            // Use MutationObserver where native Promise is not available,
-            // e.g. PhantomJS, iOS7, Android 4.4
-            // (#6466 MutationObserver is unreliable in IE11)
-            var counter = 1;
-            var observer = new MutationObserver(nextTickHandler);
-            var textNode = document.createTextNode(String(counter));
-            observer.observe(textNode, {
-                characterData: true
-            });
+        } else if (typeof MessageChannel !== 'undefined' && (isNative(MessageChannel) ||
+        // PhantomJS
+        MessageChannel.toString() === '[object MessageChannelConstructor]')) {
+            var channel = new MessageChannel();
+            var port = channel.port2;
+            channel.port1.onmessage = nextTickHandler;
             timerFunc = function timerFunc() {
-                counter = (counter + 1) % 2;
-                textNode.data = String(counter);
+                port.postMessage(1);
             };
-        } else if (typeof setImmediate !== 'undefined' && isNative(setImmediate)) {
-            // Fallback to setImmediate.
-            // Technically it leverages the (macro) task queue,
-            // but it is still a better choice than setTimeout.
+            /* istanbul ignore next */
+        } else if (typeof Promise !== 'undefined' && isNative(Promise)) {
+            // use microtask in non-DOM environments, e.g. Weex
+            var p = Promise.resolve();
             timerFunc = function timerFunc() {
-                setImmediate(nextTickHandler);
+                p.then(nextTickHandler);
             };
         } else {
-            // Fallback to setTimeout.
+            // fallback to setTimeout
             timerFunc = function timerFunc() {
                 setTimeout(nextTickHandler, 0);
             };