Info

A simple hack that I constantly use to get little performance boosts.

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    function isoneof(x) {
        var options = {};
        for (var i = 0; i < x.length; i++) options[x[i]] = true;
        return function(y) {
            return options[y] === true;
        };
    }
    
    var options = [];
    for (var i = 13; i < 100; i++) {
    options.push(String.fromCharCode(i));
    }
    
    var choices = ['a', 'k', 'z'];
    function getchoice() {
    var choices = ['a', 'k', 'z'];
    var i = Math.round(Math.random() * 3);
    return choices[i];
    }
    var decider = isoneof(options);
  };
</script>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

var i = 0;

if (choices.indexOf(getchoice()) !== -1) i++;

var i = 0;

if (decider(getchoice())) i++;

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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 Tom MacWright on 21st January 2013
• Revision 2: published by Tom MacWright on 21st January 2013

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