javascript - 正则表达式密码验证 - Codewars

Question

这个问题已经有答案了:

Regex for password must contain at least eight characters, at least one number and both lower and uppercase letters and special characters (43 个回答)

Regular Expression for alphanumeric with first alphabet and at least one alphabet and one number (2 个回答)

已关闭 8 年前。

免责声明:这是Codewars问题。

You need to write regex that will validate a password to make sure it meets the following criteria:

• At least six characters long
• contains a lowercase letter
• contains an uppercase letter
• contains a number

Valid passwords will only be alphanumeric characters.

到目前为止，这是我的尝试:

function validate(password) {
    return /^[A-Za-z0-9]{6,}$/.test(password);
}

到目前为止，它的作用是确保每个字符都是字母数字，并且密码至少有 6 个字符。它似乎在这些方面运作良好。

我被困在要求有效密码至少包含一个小写字母、一个大写字母和一个数字的部分。如何使用单个正则表达式来表达这些要求以及之前的要求？

我可以轻松地在 JavaScript 中完成此操作，但我希望仅通过正则表达式来完成此操作，因为这就是问题正在测试的内容。

Answer 1

您需要使用前瞻:

function validate(password) {
    return /^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9])[A-Za-z0-9]{6,}$/.test(password);
}

说明:

^               # start of input 
(?=.*?[A-Z])    # Lookahead to make sure there is at least one upper case letter
(?=.*?[a-z])    # Lookahead to make sure there is at least one lower case letter
(?=.*?[0-9])    # Lookahead to make sure there is at least one number
[A-Za-z0-9]{6,} # Make sure there are at least 6 characters of [A-Za-z0-9]
$               # end of input