javascript trim implementation with regexp-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_13882/article/details/82396839

本文介绍了由Steven Levithan提出的几种JavaScript字符串修剪方法及其性能对比。这些方法使用正则表达式来去除字符串首尾的空白字符。

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there is some research by Steven Levithan, who ventured to find various kind of way to implement the code that do string trimming.

he published his algorithms on this link:

http://blog.stevenlevithan.com/archives/faster-trim-javascript

Below shows some of the implementaiton that uses regular expression to do the trimming.

/**************************************
*@Summary
*  various kind of the string.trim method 
*
* 
* @Usage:
*   
* compress( "foo=1&foo=2&blah=a&blah=b&foo=3" ) == "foo=1,2,3&blah=a,b"
*
* @TODO:
* some more practical use of the string.replac method call 
*  assert("a b c".replace(/a/, function() { return ""; } ) == " b c", "returning an empty result removes a match");
***************************************/

function trim1(str) {
  return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
}

function trim2(str) {
  return str.replace(/^\s+|\s+$/g, '');
}

function trim(str) {
  var str = str.replace(/^\s\s*/, ''), 
    ws = /\s/, i = str.length;
  while (ws.test(str.charAt(--i)));
  return s.splice(0, i + 1);
}

there is no reason to do more than one impl if none has competitive advantage over another. below shows a table that compare the performance on different use cases.

Selector Trim| Document Trim

Trim1 8.7 2075.8

Trim2 8.5 3706.7

trim 13.8 169.4