substr vs regex file extension

JavaScript performance comparison

Revision 7 of this test case created

Info

For when you're testing a string for a specific filetype.

Preparation code

 
<script>
Benchmark.prototype.setup = function() {
    var regex = new RegExp(/\.json$/i),
        filename = new String('example.json');
};
</script>

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Testing in unknown unknown
Test Ops/sec
regex
(regex.test(filename));
pending…
substr
(filename.substr(-5) === '.json');
pending…
substr - i
(filename.toLowerCase().substr(-5) === '.json');
pending…
charAt
var len = filename.length;
filename.charAt(len - 1) === 'n' && filename.charAt(len - 2) === 'o' && filename.charAt(len - 3) === 's' && filename.charAt(len - 4) === 'j' && filename.charAt(len - 5) === '.';
pending…
substr - i smaller
(filename.substr(-5).toLowerCase() === '.json');
pending…
indexOf
(filename.toLowerCase().indexOf('.json', filename.length - 5)==0);
pending…

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