Native arr.forEach vs custom foreach

JavaScript performance comparison

Test case created by

Preparation code

<script>
  var i, values = [],
      sum = 0;
  for (i = 0; i < 10000; i++) {
    values[i] = i;
  }

  function add(val) {
    sum += val;
  }

  function foreach(fn) {
    var arr = this;
    var len = arr.length;
    for(var i=0; i<len; ++i) {
        fn(arr[i]);
    }
  }
  
  Object.defineProperty(Array.prototype, 'customForEach', {
    enumerable: false,
    value: foreach
  });

</script>
    

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
for loop
for (i = 0; i < values.length; i++) {
  add(values[i]);
}
pending…
forEach
values.forEach(add);
pending…
Other foreach
/*
function foreach(fn) {
    var arr = this;
    var len = arr.length;
    for(var i=0; i<len; ++i) {
        fn(arr[i]);
    }
}

Object.defineProperty(Array.prototype, 'customForEach', {
    enumerable: false,
    value: foreach
});

*/
values.customForEach(add);
pending…

Revisions

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