Loop scope

JavaScript performance comparison

Revision 2 of this test case created

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    var data = (function() {
        var r = {};
        for (var i=0; i < 1000; i++) {
            r[i] = {
                'number': i,
                'date': new Date().valueOf()
            }
        };
        return r;
    })();
  };
</script>

Test runner

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Testing in unknown unknown
Test Ops/sec
outside, same scope
 
(function() {
    
    var x;
    
    for(x in data){
        var n = x.number
    }
    
})()
 pending…
inside
 
(function() {
    
    for(var x in data){
        var n = x.number
    }
    
})()
 pending…
outside, anon function
 
(function() {
    
    var x;
    
    (function() {
        for(x in data){
            var n = x.number
        }
    })();

    
})()
 pending…
outside, declared function
 
(function() {
    
    var x;
    
    var y = function() {
        for(x in data){
            var n = x.number
        }
    }

    y();
})()
 pending…
outside, named function
 
(function() {
    
    var x;
    
    function y() {
        for(x in data){
            var n = x.number
        }
    }

    y();
})()
 pending…
outside, anon function, twice
 
(function() {
    
    var x;
    
    (function() {
        (function() {
            for(x in data){
                var n = x.number
            }
        })();
    })();

    
})()
 pending…
outside, declared function, twice
 
(function() {
    
    var x;
    
    var y = function() {
        var z = function() {
            for(x in data){
                var n = x.number
            }
        };
        z();
    }

    y();
})()
 pending…
outside, named function, twice
 
(function() {
    
    var x;
    
    function y() {
        function z(){
            for(x in data){
                var n = x.number
            }
        }
        z();
    }

    y();
})()
 pending…

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Revisions

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