javascript - 在JavaScript中遍历数组的最快方法是什么？(What's the fastest way to loop through an array in JavaScript?)

Question

I learned from books that you should write for loop like this：

(我从书中了解到，您应该为循环编写这样的内容：)

for(var i=0, len=arr.length; i < len; i++){
    // blah blah
}

so the arr.length will not be calculated each time.

(因此不会每次都计算arr.length 。)

Others say that the compiler will do some optimization to this, so you can just write:

(其他人则说编译器会对此做一些优化，因此您可以编写：)

for(var i=0; i < arr.length; i++){
    // blah blah
}

I just want to know which is the best way in practice?

(我只想知道哪种是最佳实践？)

  ask by wong2 translate from so

Answer 1

After performing this test with most modern browsers...

(在使用大多数现代浏览器执行此测试之后...)

http://jsben.ch/y3SpC

(http://jsben.ch/y3SpC)

Currently , the fastest form of loop (and in my opinion the most syntactically obvious).

(当前 ，最快的循环形式（我认为在语法上最明显）。)

a standard for loop with length caching

(具有长度缓存的循环的标准)

for (var i = 0, len = myArray.length; i < len; i++) {

}

I would say this is definitely a case where I applaud JavaScript engine developers.

(我会说这绝对是我为JavaScript引擎开发人员鼓掌的情况。)

A run time should be optimized for clarity , not cleverness .

(应该优化运行时间以提高清晰度 ， 而不是聪明 。)