isNaN() vs n !== n

JavaScript performance comparison

Revision 6 of this test case created by Jamie Pate

Preparation code

 
<script>
Benchmark.prototype.setup = function() {
    var nan = NaN;
    var val = 100;
};
</script>

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Testing in unknown unknown
Test Ops/sec
isNaN
(function() {
  "use strict";
  if (isNaN(nan)) { /* NaN */ }
  if (isNaN(val)) { /* NaN */ }
}());
pending…
v !== v
(function() {
  "use strict";
  if (nan !== nan) { /* NaN */ }
  if (val !== val) { /* NaN */ }
}());
pending…
coersion
(function() {
  "use strict";
  if (+nan !== +nan) { /* NaN */ }
  if (+val !== +val) { /* NaN */ }
}());
pending…

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