typeof vs undefined vs void(0) check (strict mode)

JavaScript performance comparison

Revision 5 of this test case created by Callum

Preparation code

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

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Testing in unknown unknown
Test Ops/sec
typeof x === "undefined"
"use strict";
typeof x === "undefined";
pending…
x === undefined
"use strict";
x === undefined;
pending…
x === void 0
"use strict";
x === void 0;
pending…

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