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

sdk/lib/core/date.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.
 
 // Dart core library.
 
 /**
  * Date is the public interface to a point in time.
  *
  * It can represent time values that are at a distance of at most
@@ skipping 243 matching lines @@
     //    - "2012-02-27 13:27:00.423z"
     //    - "20120227 13:27:00"
     //    - "20120227T132700"
     //    - "20120227"
     //    - "2012-02-27T14Z"
     //    - "-123450101 00:00:00 Z"  // In the year -12345.
     final RegExp re = const RegExp(
         r'^([+-]?\d?\d\d\d\d)-?(\d\d)-?(\d\d)'  // The day part.
         r'(?:[ T](\d\d)(?::?(\d\d)(?::?(\d\d)(.\d{1,6})?)?)? ?([zZ])?)?$');
     Match match = re.firstMatch(formattedString);
-    if (match !== null) {
+    if (match != null) {
       int parseIntOrZero(String matched) {
         // TODO(floitsch): we should not need to test against the empty string.
-        if (matched === null || matched == "") return 0;
+        if (matched == null || matched == "") return 0;
         return int.parse(matched);
       }
 
       double parseDoubleOrZero(String matched) {
         // TODO(floitsch): we should not need to test against the empty string.
-        if (matched === null || matched == "") return 0.0;
+        if (matched == null || matched == "") return 0.0;
         return double.parse(matched);
       }
 
       int years = int.parse(match[1]);
       int month = int.parse(match[2]);
       int day = int.parse(match[3]);
       int hour = parseIntOrZero(match[4]);
       int minute = parseIntOrZero(match[5]);
       int second = parseIntOrZero(match[6]);
       bool addOneMillisecond = false;
       int millisecond = (parseDoubleOrZero(match[7]) * 1000).round().toInt();
       if (millisecond == 1000) {
         addOneMillisecond = true;
         millisecond = 999;
       }
       // TODO(floitsch): we should not need to test against the empty string.
-      bool isUtc = (match[8] !== null) && (match[8] != "");
+      bool isUtc = (match[8] != null) && (match[8] != "");
       int millisecondsSinceEpoch = _brokenDownDateToMillisecondsSinceEpoch(
           years, month, day, hour, minute, second, millisecond, isUtc);
-      if (millisecondsSinceEpoch === null) {
+      if (millisecondsSinceEpoch == null) {
         throw new ArgumentError(formattedString);
       }
       if (addOneMillisecond) millisecondsSinceEpoch++;
       return new Date.fromMillisecondsSinceEpoch(millisecondsSinceEpoch,
                                                  isUtc: isUtc);
     } else {
       throw new ArgumentError(formattedString);
     }
   }
 
   static const int _MAX_MILLISECONDS_SINCE_EPOCH = 8640000000000000;
 
   _DateImpl.fromMillisecondsSinceEpoch(this.millisecondsSinceEpoch,
                                        this.isUtc) {
     if (millisecondsSinceEpoch.abs() > _MAX_MILLISECONDS_SINCE_EPOCH) {
       throw new ArgumentError(millisecondsSinceEpoch);
     }
-    if (isUtc === null) throw new ArgumentError(isUtc);
+    if (isUtc == null) throw new ArgumentError(isUtc);
   }
 
   bool operator ==(other) {
     if (!(other is Date)) return false;
     return (millisecondsSinceEpoch == other.millisecondsSinceEpoch);
   }
 
   bool operator <(Date other)
       => millisecondsSinceEpoch < other.millisecondsSinceEpoch;
 
@@ skipping 97 matching lines @@
   external Duration get timeZoneOffset;
   external int get year;
   external int get month;
   external int get day;
   external int get hour;
   external int get minute;
   external int get second;
   external int get millisecond;
   external int get weekday;
 }