"Type of undefined" vs "=== undefined" (v52)

Revision 52 of this benchmark created by hoochieminh on

Description

added scopes to determine whether scope traversal matters (for undefined).

Setup

var a = 1,
      b = true,
      c = "c",
      d = [],
      e = {},
      f;
    
    function testTypeOf() {
      typeof a === 'undefined';
      typeof b === 'undefined';
      typeof c === 'undefined';
      typeof d === 'undefined';
      typeof e === 'undefined';
      typeof f === 'undefined';
    }
    
    function testEqualityWin() {
      a === window.undefined;
      b === window.undefined;
      c === window.undefined;
      d === window.undefined;
      e === window.undefined;
      f === window.undefined;
    }
    
    function testEquality() {
      a === undefined;
      b === undefined;
      c === undefined;
      d === undefined;
      e === undefined;
      f === undefined;
    }
    
    function testVoid0() {
    a === void 0;
    b === void 0;
    c === void 0;
    d === void 0;
    e === void 0;
    f === void 0;
    }

Test runner

Ready to run.

Testing in
TestOps/sec
typeof undefined
testTypeOf();
ready
=== undefined
testEquality();
ready
void 0
testVoid0(0);
ready
testEqualityWin
testEqualityWin();
ready

Revisions

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