undefined vs typeof

JavaScript performance comparison

Test case created by Josh

Preparation code

 
<script>
Benchmark.prototype.setup = function() {
    var foo;
};
</script>

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Testing in unknown unknown
Test Ops/sec
eq undefined
if (foo === undefined) {
  // yay
}
pending…
typeof undefined
if (typeof foo === "undefined") {
 // weeeeeeee
}
pending…

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