如何使用matches(regex)验证用户名? [英] How to validate usernames using matches(regex)?

问题描述

我正在尝试将以下表达式放入matchs函数中，但是在尝试编译规则时我猜错了.

I'm trying to put the following expression into the matches function but I guess errors when trying to compile the rules.

 ^[a-zA-Z](([\._\-][a-zA-Z0-9])|[a-zA-Z0-9])*[a-z0-9]$

.validate规则如下:

".validate": "newData.val() === auth.uid         
&& newData.val().matches(^(?=.{5,10}$)(?!.*[._-]{2})[a-z][a-z0-9._-]*[a-z0-9]$)" 

我得到:

" Invalid escape: '\.'"

推荐答案

看来您无法在Firebase中使用环顾四周，因此应调整您的模式和整个方法以解决此问题.

It appears you cannot use lookarounds in Firebase, so your pattern and the whole approach should be adjusted to account for that.

您当前的正则表达式需要5到10个符号的字符串长度，并且不允许使用两个连续的符号.，_和-.第一个条件应使用诸如newData.val().length >= 5 && newData.val().length <= 10之类的代码在正则表达式之外进行检查，第二个条件仅需要重新分组和重新量化:

Your current regex requires a string length from 5 to 10 symbols, and disallows 2 consecutive symbols ., _ and -. The first condition should be checked outside the regex with some code like newData.val().length >= 5 && newData.val().length <= 10 and the second one just requires re-grouping and re-quantifying:

.matches(/^[a-z][a-z0-9]*([._-][a-z0-9]+)*$/)

请参见正则表达式演示.

详细信息:

• ^-字符串开头
• [a-z]-小写字母(如果在末尾添加/i，将区分大小写)
• [a-z0-9]*-零个或多个a-z和0-9符号
• ([._-][a-z0-9]+)*-一个.，_或-，后跟一个或多个(如果存在.，<字符串中的c2>或-)来自0-9和a-z范围的字符
• $-字符串锚点的结尾.

• ^ - start of string
• [a-z] - a lowercase letter (if you add /i at the end, it will be case sensitive)
• [a-z0-9]* - zero or more a-z and 0-9 symbols
• ([._-][a-z0-9]+)* - a ., _ or - followed with one or more (this requires [a-z0-9] to be at the end if there is ., _ or - in the string) characters from 0-9 and a-z ranges
• $ - the end of string anchor.

请注意，您不必转义字符类中的字符，因为其中的.和_不是特殊字符，并且-在方括号表达式(字符类)的末尾或开头是文字连字符.

Note you do not need to escape the characters inside the character class as the . and _ are not special chars inside it, and the - at the end or start of the bracket expression (character class) is a literal hyphen.

这篇关于如何使用matches(regex)验证用户名?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！