Info

Simple test that compares speed of two methods to format bytes to human-readable format.

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    var results = [
        10240,
        10485760,
        10737418240,
        10995116277760,
        11258999068426240
        ],
        sizes = [
                "B",
                "kB",
                "MB",
                "GB",
                "TB"
                ],
        strings = {
        "na": "n/a"
    },
        undefined;
        
    
    function formatBytesNew(bytes) {
        if (bytes === undefined || bytes === '0' || isNaN(bytes)) {
                return strings.na;
        }
        // 6.931471805599453 = Math.log(1024);
        var i = ~~ (Math.log(bytes) / 6.931471805599453);
        return ~~ (0.5 + bytes / results[i]) / 10 + ' ' + sizes[i];
    }
    
    function formatBytesOld(bytes) {
        if (bytes === undefined || bytes === '0' || isNaN(bytes)) {
                return strings.na;
        }
        // 6.931471805599453 = Math.log(1024);
        var i = ~~ (Math.log(bytes) / 6.931471805599453);
        return Math.round(bytes / results[i]) / 10 + ' ' + sizes[i];
    }
  };
</script>

Test runner

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formatBytesOld(66666);

formatBytesNew(66666);

formatBytesOld(66666666666);

formatBytesNew(66666666666);

Compare results of other browsers

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 by Mr. X on 15th December 2011
• Revision 2: published by Mr. X on 16th December 2011
• Revision 3: published by Mr. X on 16th December 2011
• Revision 4: published by Mr. X on 1st February 2012

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