Merge pull request facebook#5391 from zjjw/transition_timeouts

Clear transition timeouts when component unmounts. Fixes facebook#4876

src/addons/transitions/ReactCSSTransitionGroupChild.js

@@ -100,6 +100,7 @@ var ReactCSSTransitionGroupChild = React.createClass({
     if (userSpecifiedDelay) {
       // Clean-up the animation after the specified delay
       timeout = setTimeout(endListener, userSpecifiedDelay);
+      this.transitionTimeouts.push(timeout);
     } else {
       // DEPRECATED: this listener will be removed in a future version of react
       ReactTransitionEvents.addEndEventListener(node, endListener);
@@ -126,12 +127,16 @@ var ReactCSSTransitionGroupChild = React.createClass({
 
   componentWillMount: function() {
     this.classNameQueue = [];
+    this.transitionTimeouts = [];
   },
 
   componentWillUnmount: function() {
     if (this.timeout) {
       clearTimeout(this.timeout);
     }
+    this.transitionTimeouts.forEach(function(timeout) {
+      clearTimeout(timeout);
+    });
   },
 
   componentWillAppear: function(done) {

src/addons/transitions/__tests__/ReactCSSTransitionGroup-test.js

@@ -269,4 +269,26 @@ describe('ReactCSSTransitionGroup', function() {
     var leavingNode = ReactDOM.findDOMNode(a).childNodes[0];
     expect(CSSCore.hasClass(leavingNode, 'custom-leaving')).toBe(true);
   });
+
+  it('should clear transition timeouts when unmounted', function() {
+    var Component = React.createClass({
+      render: function() {
+        return (
+          <ReactCSSTransitionGroup
+            transitionName="yolo"
+            transitionEnterTimeout={500}>
+            {this.props.children}
+          </ReactCSSTransitionGroup>
+        );
+      },
+    });
+
+    ReactDOM.render(<Component/>, container);
+    ReactDOM.render(<Component><span key="yolo" id="yolo"/></Component>, container);
+
+    ReactDOM.unmountComponentAtNode(container);
+
+    // Testing that no exception is thrown here, as the timeout has been cleared.
+    jest.runAllTimers();
+  });
 });