a === b -> identical(a, b)

samples/swarm/swarm_ui_lib/touch/ClickBuster.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Click buster implementation, which is a behavior that prevents native clicks
  * from firing at undesirable times. There are two scenarios where we may want
  * to 'bust' a click.
  *
  * Buttons implemented with touch events usually have click handlers as well.
@@ skipping 157 matching lines @@
     //       temporary "allowable zone".
     //     - preventGhostClick is called and removes the "allowable zone".
     //     - The click handler captures the user's click event and prevents it
     //       from propagating since there is no "allowable zone".
     //
     //   3) User performs a should-not-be-busted click.
     //     - touchstart event triggers the attached handler and creates a
     //       temporary "allowable zone".
     //     - The click handler captures the user's click event and allows it to
     //       propagate since the click falls in the "allowable zone".
-    if (_coordinates === null) {
+    if (_coordinates == null) {
       // Listen to clicks on capture phase so they can be busted before anything
       // else gets a chance to handle them.
       document.on.click.add((e) { _onClick(e); }, true);
       document.on.focus.add((e) { _lastPreventedTime = 0; }, true);
 
       // Listen to touchstart on capture phase since it must be called prior to
       // every click or else we will accidentally prevent the click even if we
       // don't call preventGhostClick.
       Function startFn = (e) { _onTouchStart(e); };
       if (!Device.supportsTouch) {
@@ skipping 16 matching lines @@
       if (_hitTest(entry.element, entry.nextEntry().element, x, y)) {
         entry.nextEntry().remove();
         entry.remove();
         return;
       } else {
         entry = entry.nextEntry().nextEntry();
       }
     }
   }
 }