Info

Stackoverflow - http://stackoverflow.com/q/8699357/918414

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
        var items1 = ['txfa2', 'txfa9', 'txfa2', 'txfa1', 'txfa3', 'txfa4', 'txfa8', 'txfa9', 'txfa2', 'txfa8'];
        var items2 = ['txfa2', 'txfa9', 'txfa2', 'txfa1', 'txfa3', 'txfa4', 'txfa8', 'txfa9', 'txfa2', 'txfa8', 'txfa9', 'txfa2', 'txfa1', 'txfa3', 'txfa4'];
        var items3 = ['txfa2', 'txfa2', 'txfa2', 'txfa2', 'txfa2', 'txfa2', 'txfa2', 'txfa2', 'txfa2', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa7'];
        var items4 = ['txfa2', 'txfa2', 'txfa2', 'txfa3', 'txfa4', 'txfa2', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa2', 'txfa2', 'txfa4', 'txfa9', 'txfa7', 'txfa7', 'txfa7', 'txfa7', 'txfa7'];
    
    function singlesIndexOf( array ) {
        for( var index = 0, single = []; index < array.length; index++ ) {
            if( array.indexOf( array[index], array.indexOf( array[index] ) + 1 ) == -1 ) single.push( array[index] );    
        };
        return single;
    };
    
    
    
    
    function singlesJSObject( array ) {
    
        var result = []
          , i
          , k
          , container = {};
        
        for (i = 0; i < array.length; ++i) {
          if (array[i] in container) {
            container[array[i]]++;
          } else {
            container[array[i]] = 1;
          }
        }
        for (k in container) {
          if (container[k] == 1) {
            result.push(k);
          }
        }
    
        return result;
        
    };
    
    
    function singlesReduce( array ) {
    
        // create a map from value -> count(value)
        var keys = array.reduce(function(o, k) {
           o[k] = o[k] ? o[k] + 1 : 1;
           return o;
        }, {});
    
        // find those that only appeared once
        return Object.getOwnPropertyNames(keys).filter(function(k) {
            return (keys[k] === 1);
        });
    }
  };
</script>

Test runner

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

Java applet disabled.

var singles = singlesIndexOf( items1 );
var singles = singlesIndexOf( items2 );
var singles = singlesIndexOf( items3 );
var singles = singlesIndexOf( items4 );
 

var singles = singlesJSObject( items1 );
var singles = singlesJSObject( items2 );
var singles = singlesJSObject( items3 );
var singles = singlesJSObject( items4 );
 

var singles = singlesReduce( items1 );
var singles = singlesReduce( items2 );
var singles = singlesReduce( items3 );
var singles = singlesReduce( items4 );
 

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 ThinkingStiff on 2nd January 2012
• Revision 2: published on 2nd January 2012
• Revision 3: published by ThinkingStiff on 2nd January 2012 and last updated on 3rd January 2012

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