Merge pull request #2181 from zpao/move-onscroll-detection

Move onscroll detection

src/browser/ui/ReactDOMComponent.js

@@ -31,9 +31,11 @@ var ReactPerf = require('ReactPerf');
 
 var escapeTextForBrowser = require('escapeTextForBrowser');
 var invariant = require('invariant');
+var isEventSupported = require('isEventSupported');
 var keyOf = require('keyOf');
 var merge = require('merge');
 var mixInto = require('mixInto');
+var monitorCodeUse = require('monitorCodeUse');
 
 var deleteListener = ReactBrowserEventEmitter.deleteListener;
 var listenTo = ReactBrowserEventEmitter.listenTo;
@@ -66,6 +68,15 @@ function assertValidProps(props) {
 }
 
 function putListener(id, registrationName, listener, transaction) {
+  if (__DEV__) {
+    // IE8 has no API for event capturing and the `onScroll` event doesn't
+    // bubble.
+    if (registrationName === 'onScroll' &&
+        !isEventSupported('scroll', true)) {
+      monitorCodeUse('react_no_scroll_event');
+      console.warn('This browser doesn\'t support the `onScroll` event');
+    }
+  }
   var container = ReactMount.findReactContainerForID(id);
   if (container) {
     var doc = container.nodeType === ELEMENT_NODE_TYPE ?

src/browser/ui/__tests__/ReactDOMComponent-test.js

@@ -418,4 +418,26 @@ describe('ReactDOMComponent', function() {
     });
   });
 
+  describe('onScroll warning', function() {
+    it('should warn about the `onScroll` issue when unsupported (IE8)', () => {
+      // Mock this here so we can mimic IE8 support. We require isEventSupported
+      // before React so it's pre-mocked before React qould require it.
+      require('mock-modules')
+        .dumpCache()
+        .mock('isEventSupported');
+      var isEventSupported = require('isEventSupported');
+      isEventSupported.mockReturnValueOnce(false);
+
+      var React = require('React');
+      var ReactTestUtils = require('ReactTestUtils');
+
+      spyOn(console, 'warn');
+      ReactTestUtils.renderIntoDocument(<div onScroll={function(){}} />);
+      expect(console.warn.callCount).toBe(1);
+      expect(console.warn.mostRecentCall.args[0]).toBe(
+        'This browser doesn\'t support the `onScroll` event'
+      );
+    });
+  });
+
 });

src/event/EventPluginHub.js

@@ -24,8 +24,6 @@ var EventPluginUtils = require('EventPluginUtils');
 var accumulateInto = require('accumulateInto');
 var forEachAccumulated = require('forEachAccumulated');
 var invariant = require('invariant');
-var isEventSupported = require('isEventSupported');
-var monitorCodeUse = require('monitorCodeUse');
 
 /**
  * Internal store for event listeners
@@ -159,15 +157,6 @@ var EventPluginHub = {
       registrationName, typeof listener
     );
 
-    if (__DEV__) {
-      // IE8 has no API for event capturing and the `onScroll` event doesn't
-      // bubble.
-      if (registrationName === 'onScroll' &&
-          !isEventSupported('scroll', true)) {
-        monitorCodeUse('react_no_scroll_event');
-        console.warn('This browser doesn\'t support the `onScroll` event');
-      }
-    }
     var bankForRegistrationName =
       listenerBank[registrationName] || (listenerBank[registrationName] = {});
     bankForRegistrationName[id] = listener;

src/event/__tests__/EventPluginHub-test.js

@@ -33,15 +33,6 @@ describe('EventPluginHub', function() {
     isEventSupported.mockReturnValueOnce(false);
   });
 
-  it('should warn about the `onScroll` issue on IE8', function() {
-    spyOn(console, 'warn');
-    EventPluginHub.putListener(1, 'onScroll', function(){});
-    expect(console.warn.callCount).toBe(1);
-    expect(console.warn.mostRecentCall.args[0]).toBe(
-      'This browser doesn\'t support the `onScroll` event'
-    );
-  });
-
   it("should prevent non-function listeners", function() {
     expect(function() {
       EventPluginHub.putListener(1, 'onClick', 'not a function');