foreach-bench.js

#!/usr/bin/env node-bench


var list = [
  "foo",
  "bar",
  "baz",
  "quux",
  "asdf",
  "qwerty",
  "bonk",
  "whack",
  "zoom",
  "zap"
];

exports.compare = {
  forEach : function () {
    var len = 0;
    list.forEach(function (item) {
      len += item.length;
    });
  },
  length : function () {
    for (var len = 0, i = 0; i < list.length; i ++) {
      len += list[i].length;
    }
  },
  lengthCached : function () {
    for (var len = 0, i = 0, l = list.length; i < l; i ++) {
      len += list[i].length;
    }
  },
  lengthCached2 : function () {
    for (var len = 0, i = 0, l = list.length; i < l; ) {
      len += list[ i++ ].length;
    }
  },
  lengthWithFn : function () {
    function f (l) { len += l };
    for (var len = 0, i = 0; i < list.length; i ++) {
      f(list[i].length);
    }
  }
};

output.txt

jedbook:gist-288266 jed$ node-bench foreach-bench.js 
benchmarking /Users/jed/Desktop/gist-288266/foreach-bench
Please be patient.
Scores: (bigger is better)

lengthCached2
Raw:
 > 6358.358358358359
 > 6390
Average (mean) 6374.179179179179

lengthCached
Raw:
 > 6147
 > 6244
Average (mean) 6195.5

length
Raw:
 > 4536
 > 4517
Average (mean) 4526.5

lengthWithFn
Raw:
 > 2277
 > 2279.72027972028
Average (mean) 2278.36013986014

forEach
Raw:
 > 2042.9570429570429
 > 2033
Average (mean) 2037.9785214785215

Winner: lengthCached2
Compared with next highest (lengthCached), it's:
2.8% faster
1.03 times as fast
0 order(s) of magnitude faster

Compared with the slowest (forEach), it's:
68.03% faster
3.13 times as fast
0 order(s) of magnitude faster