哪个regexp更快

Which regexp is faster?

本文关键字：更快 regexp 哪个      更新时间：2023-09-26

如果我想匹配A或a，下面的regexp中哪一个会更快？

/[Aa]/

或

/A/i

它有多少步骤？

试着这样检查：

function time_my_script(script) {
    var start = window.performance.now();
    script();
    return window.performance.now() - start;
}
time_a = time_my_script(function() {
    var text = 'This is a test string, make it a long one to actually test well';
    var patt = new RegExp(/[Aa]/);
    var res = patt.test(text);
});
time_b = time_my_script(function() {
    var text = 'This is a test string, make it a long one to actually test well';
    var patt = new RegExp(/A/i);
    var res = patt.test(text);
});
console.log('Time A ' + time_a);
console.log('Time B ' + time_b);

JSFiddle：https://jsbin.com/gasayarivu/edit?js，控制台

附言：
对于异步脚本，这可能会有点困难。

相关文章：