fn.call(何か) ベンチ

js 高速化

気になったのでとってみたけどあまり意味が無いベンチになりました。fn.call(null) って速いのね。

Browser fn.call(null) fn.call(this) fn.call(window) (function(){fn()}
Fx3.6 1162 5911 3630 6432
IE8 937 1010 1073 2338
IE6 2833 2447 2578 5093
GC6 304 285 1452 403
Sa5 288 323 280 2002
iSa4 69 67 65 300
Op10.6x 1916 1970 4066 2287
Total 7509 12013 13144 18855


bench.js は http://pigs.sourceforge.jp/blog/20100722 にあります

<!DOCTYPE html><html lang="ja"><head><meta charset="utf-8" />
<title>bench: call(hoge)</title>
<style>th,td { padding: 5px; text-align: right }</style>
<script src="bench.js"></script><script>

window.onload = function() {

    document.body.innerHTML += "<p>" + navigator.userAgent + "</p>Running...";

    var loop = getLoop();

    // ---------------------------------------------------------
    var _ary = [0, 1, 2, 3, 4];

    function callback(value, index) {
        return index * value;
    }

    function _call_null(idx) {
        var ary = _ary, i = 0, iz = ary.length;

        for (; i < iz; ++i) {
            callback.call(null, ary[i], i);
        }
        return idx;
    }

    function _call_this(idx) {
        var ary = _ary, i = 0, iz = ary.length;

        for (; i < iz; ++i) {
            callback.call(this, ary[i], i);
        }
        return idx;
    }

    function _call_window(idx) {
        var ary = _ary, i = 0, iz = ary.length;

        for (; i < iz; ++i) {
            callback.call(window, ary[i], i);
        }
        return idx;
    }

    function _func(idx) {
        var ary = _ary, i = 0, iz = ary.length;

        for (; i < iz; ++i) {
            (function(value, index) {
                callback(value, index);
            })(ary[i], i);
        }

        return idx;
    }

    job(5, loop, ["callback.call(null)", _call_null,
                  "callback.call(this)", _call_this,
                  "callback.call(window)", _call_window,
                  "(function(){callback()}",  _func]);
}
</script></head><body></body></html>