fastest isArray (v4)

Revision 4 of this benchmark created by Thomas Aylott on July 31, 2011

Preparation HTML

<script>
  var Object__toString = {}.toString;
  
  var isArrayN = Array.isArray;
  
  function isArray1(object) {
   return object != null && Object__toString.call(object) === "[object Array]";
  }
  
  function isArray2(object) {
   if (object == null || !object.valueOf) return false;
   if (object instanceof Array) return true;
   return Object__toString.call(object) === "[object Array]";
  }
  
  function isArrayWithInstanceof(object) {
   return object instanceof Array
  }
  
  
</script>

Test runner

var a = Array.isArray(null);
var b = Array.isArray({});
var c = Array.isArray([]);

var a = isArray1(null);
var b = isArray1({});
var c = isArray1([]);

var a = isArray2(null);
var b = isArray2({});
var c = isArray2([]);

var a = isArrayN(null);
var b = isArrayN({});
var c = isArrayN([]);

var a = isArrayWithInstanceof(null);
var b = isArrayWithInstanceof({});
var c = isArrayWithInstanceof([]);

var a = null instanceof Array;
var b = {} instanceof Array;
var c = [] instanceof Array;
 

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.

• Revision 4: published by Thomas Aylott on July 31, 2011