for-loop vs. for-in-loop (v44)

Revision 44 of this benchmark created on

Description

Testing the speed of iterating various sized arrays with straight for-loop or with a for-in-loop over its keys.

Preparation HTML

<script>
var _len = 1000000;
var _aut = new Array(_len);

for (var _i = 0; _i < _len; _i++) {
    _aut[_i] = {value:_i};
}

function _genFilterFn(itemName, condition) {
    var _iteratorName = '_i';
    var _inputArrayLenName = '_len';
    var _outputArrayName = '_result';

    var _fnBody =
        '\tvar ' + _iteratorName + ' = 0,\n\t\t' + _inputArrayLenName + ' = this.length,\n\t\t' + _outputArrayName + ' = [],\n\t\t' + itemName + ',_k=0;\n\n' +

        '\twhile (' + _iteratorName + '++ < ' + _inputArrayLenName + ') {\n' +
        '\t\t' + itemName + ' = this[' + _iteratorName + '];\n\n' +
        '\t\tif (' + condition + ') {\n' +
        '\t\t\t' + _outputArrayName + '[_k++] = ' + itemName + ';\n' +
        '\t\t}\n' +
        '\t}\n\n' +

        '\treturn ' + _outputArrayName + ';';

    return new Function(_fnBody);
}

var _nativeFilterFn = function _filter(item) {
    return !!(item.value & 1);
};
var _generatedFilterFn = _genFilterFn('item', '!!(item.value & 1)');
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
native
_aut.filter(_nativeFilterFn);
ready
generated
_generatedFilterFn.call(_aut);
ready

Revisions

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