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

samples/third_party/dromaeo/tests/dom-traverse-html.dart

 library dom_traverse;
 import 'dart:html';
 import '../common/common.dart';
 import 'dart:math' as Math;
 part 'Common.dart';
 part 'RunnerSuite.dart';
 
 
 void main() {
   final int num = 40;
@@ skipping 20 matching lines @@
       div.innerHTML = html;
       document.body.$dom_appendChild(div);
     })
     .test('firstChild', () {
       final nodes = document.body.$dom_childNodes;
       final nl = nodes.length;
 
       for (int i = 0; i < num; i++) {
         for (int j = 0; j < nl; j++) {
           Node cur = nodes[j];
-          while (cur !== null) {
+          while (cur != null) {
             cur = cur.$dom_firstChild;
           }
           ret = cur;
         }
       }
     })
     .test('lastChild', () {
       final nodes = document.body.$dom_childNodes;
       final nl = nodes.length;
 
       for (int i = 0; i < num; i++) {
         for (int j = 0; j < nl; j++) {
           Node cur = nodes[j];
-          while (cur !== null) {
+          while (cur != null) {
             cur = cur.$dom_lastChild;
           }
           ret = cur;
         }
       }
     })
     .test('nextSibling', () {
       for (int i = 0; i < num * 2; i++) {
         Node cur = document.body.$dom_firstChild;
-        while (cur !== null) {
+        while (cur != null) {
           cur = cur.nextNode;
         }
         ret = cur;
       }
     })
     .test('previousSibling', () {
       for (int i = 0; i < num * 2; i++) {
         Node cur = document.body.$dom_lastChild;
-        while (cur !== null) {
+        while (cur != null) {
           cur = cur.previousNode;
         }
         ret = cur;
       }
     })
     .test('childNodes', () {
       for (int i = 0; i < num; i++) {
         final nodes = document.body.$dom_childNodes;
         for (int j = 0; j < nodes.length; j++) {
           ret = nodes[j];
         }
       }
     })
     .end();
 }