Info

Check performance of === vs == in varying situations.

Preparation code

<script>
  var u = undefined,
      i = 0,
      a = "0",
      n = null,
      e = '',
  isU = function (v) { return typeof u === 'undefined'; },
  isN = function (v) { return u === null; },
  isUN = function (v) { return typeof u !== 'undefined' && u !== null; },
  isUNfn = function (v) { return !isU(v) && !isN(v); },
  isUNb = function (v) { return !!!v; };
</script>

Test runner

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if (u === undefined) {
 e = '';
}

if (u == undefined) {
 e = '';
}

if (typeof u === 'undefined') {
 e = '';
}

if (typeof u == 'undefined') {
 e = '';
}

if (i === 0) {
 e = '';
}

if (i == 0) {
 e = '';
}

if (i === '0') {
 e = '';
}

if (i == '0') {
 e = '';
}

if (a === 0) {
 e = '';
}

if (a == 0) {
 e = '';
}

if (a === '0') {
 e = '';
}

if (a == '0') {
 e = '';
}

if (n === null) {
 e = '';
}

if (n == null) {
 e = '';
}

if (n === 0) {
 e = '';
}

if (e === '') {
 e = '';
}

if (e == '') {
 e = '';
}

if (e.length === 0) {
 e = '';
}

if (e.length == 0) {
 e = '';
}

if (e.length !== 0) {
 e = '';
}

if (e.length != 0) {
 e = '';
}

if (e.length) {
 e = '';
}

if (u) {
e = '';
}

if (!u) {
e = '';
}

if (!!u) {
e = '';
}

if (!!!u) {
e = '';
}

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Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:

• Revision 1: published on 3rd June 2011
• Revision 2: published on 3rd June 2011
• Revision 3: published by Mike McCaughan on 6th July 2011
• Revision 4: published by Mike McCaughan on 13th October 2011
• Revision 5: published by Mike McCaughan on 13th October 2011
• Revision 6: published by Mike McCaughan on 13th October 2011
• Revision 7: published by Mike McCaughan on 6th December 2011
• Revision 8: published on 22nd March 2013

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