Javascript 切换与 if...else if...else

2022-01-20 00:00:00 conditional javascript cross-browser

各位,我有几个问题:

  1. switch 语句和 if...else 在 JavaScript 中是否存在性能差异?
  2. 如果是,为什么?
  3. switchif...else 的行为在浏览器中是否不同?(FireFox、IE、Chrome、Opera、Safari)
  1. Is there a performance difference in JavaScript between a switch statement and an if...else?
  2. If so why?
  3. Is the behavior of switch and if...else different across browsers? (FireFox, IE, Chrome, Opera, Safari)

问这个问题的原因是,我似乎在 Firefox 中使用大约 1000 个案例的 switch 语句获得了更好的性能.

The reason for asking this question is it seems that I get better performance on a switch statement with approx 1000s cases in Firefox.

已编辑不幸的是,这不是我的代码,Javascript 是从已编译的库在服务器端生成的,我无权访问该代码.生成 javascript 的方法称为

Edited Unfortuantly this is not my code the Javascript is being produced serverside from a compiled library and I have no access to the code. The method that is producing the javascript is called

CreateConditionals(string name, string arrayofvalues, string arrayofActions)

注意 arrayofvalues 是一个逗号分隔的列表.

note arrayofvalues is a comma separated list.

它产生的是什么

function [name] (value) {
  if (value == [value from array index x]) {
     [action from array index x]
  }
}

注意:其中 [name] = 传入服务器端函数的名称

Note: where [name] = the name passed into the serverside function

现在我将函数的输出更改为要插入到 TextArea 中,编写一些 JavaScript 代码来解析该函数​​,并将其转换为一组 case 语句.

Now I changed the output of the function to be inserted into a TextArea, wrote some JavaScript code to parse through the function, and converted it to a set of case statements.

最后我运行了这个函数,它运行良好,但在 IE 和 Firefox 中性能不同.

finally I run the function and it runs fine but performance differs in IE and Firefox.

推荐答案

笼统回答:

  1. 是的,通常情况下.
  2. 在此处查看更多信息
  3. 是的,因为每个都有不同的 JS 处理引擎,但是,在下面的站点上运行测试时,switch 总是在大量迭代中执行 if、elseif.

测试站点

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