注: array数组默认为空, 依次赋值数组长度为1 000 000, 10 000 000, 100 000 000, 分别在 Chrome, Firefox, Safari 浏览器上进行两轮测试, 取测试时间平均值作为比较对象, 时间单位为ms. 如下是测试代码:
var array = [], length = array.length = 10000000;//(一千万) //for(var i=0;i<length;i++){ // array[i] = 'louis'; //} console.log(array[0]); //-------------------------for var t1 = +new Date(); for(var i=0;i<length;i++){ } var t2 = +new Date(); console.log('for:' + (t2-t1)); //-------------------------do/while var t1 = +new Date(); var i = 0; do { i++; } while(i<length); var t2 = +new Date(); console.log('do while:' + (t2-t1)); //-------------------------forEach var t1 = +new Date(); array.forEach(function(item){ }); var t2 = +new Date(); console.log('forEach:' + (t2-t1)); //-------------------------for in var t1 = +new Date(); for(var item in array){ } var t2 = +new Date(); console.log('for in:' + (t2-t1)); //------------------------- $.each var t1 = +new Date(); $.each(array, function(i, ele){ }); var t2 = +new Date(); console.log('$.each:' + (t2-t1)); //-------------------------$().each var t1 = +new Date(); $(array).each(function(i,ele){ }); var t2 = +new Date(); console.log('$(ele).each:' + (t2-t1)); //-------------------------map var t1 = +new Date(); array.map(function(num){ }); var t2 = +new Date(); console.log('map:' + (t2-t1)); //-------------------------every var t1 = +new Date(); array.every(function(e,i,arr){ }); var t2 = +new Date(); console.log('every:' + (t2-t1));
测试机器正常运行 IDE, 编辑器, 浏览器, qq, 微信等常用应用, 系统空闲. 硬件设备如下:
操作系统: OSX EI Capitan 版本 10.11.5
MacBook Pro（13 英寸，2015 年初期）
处理器: 2.7 GHz Intel Core i5
内存: 8 GB 1867 MHz DDR3
以上多轮测试结果汇总如下三张表(单位:ms):
数组长度为10^6
数组长度为10^6
chrome 52.0.2743.116 (64-bit)
Firefox Developer Edition 49.0a2 (2016-08-01)
Safari 9.1.1 (11601.6.17)
for
(16+19)/2 = 17.5
(6+7)/2 = 6.5
(6+7)/2 = 6.5
do while
(24+17)/2 = 20.5
(7+5)/2 = 6
(5+5)/2 = 5
for in
(19+28)/2 = 23.5
(0+0)/2 = 0
(0+0)/2 = 0
forEach
(41+28)/2 = 34.5
(4+4)/2 = 4
(31+29)/2 = 30
map
(26+32)/2 = 28
(4+4)/2 = 4
(32+26)/2 = 28
every
(22+24)/2 = 23
(4+5)/2 = 4.5
(41+45)/2 = 43
$.each
(29+27)/2 = 28
(306+311)/2 = 308.5
(111+97)/2 = 104
$(e).each
(94+98)/2 = 96
(484+488)/2 = 486
(79+64)/2 = 71.5
数组长度为10^7