javascript - 正则表达式用于验证给定字符串中至少 n 个大写字母、小写字母、数字和特殊字符

Question

我需要添加为每种类型(大写、小写、数字和特殊)字符提供最少字符(范围 0 - 9)的功能密码。

我发现了很多解决方案，它们为至少 1 个特殊/大写/小写/数字( Regex for Password: "Atleast 1 letter, 1 number, 1 special character and SHOULD NOT start with a special character" )提供了解决方案，但没有通用的解决方案可以满足我的要求。

我在下面尝试了字符串中至少 n 个特殊字符，但它不起作用。

function CheckSpecialChars(n, NewPassword){
  var PasswordPattern ="^(?=.*[a-zA-Z])(?=.*\\d)(?=.*[!@#$%^&*()_+]{n})[A-Za-z\\d!@#$%^&*()_+]{8,20}$";
  var NewPassword = $('#txt').val();
  var PasswordRegEx = new RegExp(PasswordPattern, 'g');
  if (!PasswordRegEx.test(NewPassword)) {
    $('.er').html('not matched');
    return false;
  }else{
    $('.er').html('matched');
    return false;
  }
}

// if minimum 2 special characters are mandatory
Valid String: sad@j234KSS&ff // has more than 2 special chars
Invalid String: sdf#kj034950 // has less than 2 special chars

Answer 1

您需要使用构造函数构造正则表达式，因为 n 是变量。这是一个例子:

使用n = 2构造正则表达式:

var n = 2;
var constructedRegEx = "^(?=(?:.*[0-9]){" + n + ",})(?=(?:.*[a-z]){" + n + ",})(?=(?:.*[A-Z]){" + n + ",})(?=(?:.*[[!@#$%^&*()_+]){" + n + ",}).+$";

var PasswordRegEx = new RegExp(constructedRegEx, 'm');

console.log(PasswordRegEx.test('@Al1#a2B'));
console.log(PasswordRegEx.test('@Al1#a2'));

构造正则表达式的示例:

^(?=(?:.*[0-9]){2,})(?=(?:.*[a-z]){2,})(?=(?:.*[A-Z]){2,})(?=(?:.*[!@#$%^&*]){2,}).+$

铁路图:

描述:

    NODE                     EXPLANATION
----------------------------------------------------------------------
  ^                        the beginning of a "line"
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    (?:                      group, but do not capture (at least 2
                             times (matching the most amount
                             possible)):
----------------------------------------------------------------------
      .*                       any character except \n (0 or more
                               times (matching the most amount
                               possible))
----------------------------------------------------------------------
      [0-9]                    any character of: '0' to '9'
----------------------------------------------------------------------
    ){2,}                    end of grouping
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    (?:                      group, but do not capture (at least 2
                             times (matching the most amount
                             possible)):
----------------------------------------------------------------------
      .*                       any character except \n (0 or more
                               times (matching the most amount
                               possible))
----------------------------------------------------------------------
      [a-z]                    any character of: 'a' to 'z'
----------------------------------------------------------------------
    ){2,}                    end of grouping
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    (?:                      group, but do not capture (at least 2
                             times (matching the most amount
                             possible)):
----------------------------------------------------------------------
      .*                       any character except \n (0 or more
                               times (matching the most amount
                               possible))
----------------------------------------------------------------------
      [A-Z]                    any character of: 'A' to 'Z'
----------------------------------------------------------------------
    ){2,}                    end of grouping
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    (?:                      group, but do not capture (at least 2
                             times (matching the most amount
                             possible)):
----------------------------------------------------------------------
      .*                       any character except \n (0 or more
                               times (matching the most amount
                               possible))
----------------------------------------------------------------------
      [!@#0^&*]                any character of: '!', '@', '#', '0',
                               '^', '&', '*'
----------------------------------------------------------------------
    ){2,}                    end of grouping
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  .+                       any character except \n (1 or more times
                           (matching the most amount possible))
----------------------------------------------------------------------
  $                        before an optional \n, and the end of a
                           "line"
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

<强> Regex101