javascript to validate random characters in password like "a1a, aKa, a$a, aJ^lG, G78%s#

Question

I am having a password change page where I want to validate my password with "2 small letters, 2 capital letters, 3 symbols, 2 digits and so on. Now from the below code I am able to just validate the password in sequence like "aa, KK,ap, JK, 90, 89" but not working for " aK9Ju, a^rtH, hGT5$u etc.

I am just pasting code for small letters, If you want I can provide the entire code.

psw.onkeyup = function() {
var LC = jsonData.LOWERCASE;
var psw = document.getElementById("psw").value.replace(/([a-z])\d+/g, '$1');
var lowerCaseLetters = new RegExp('[a-z]{' + LC + '}', 'g')
if(psw.match(lowerCaseLetters)) {
letter.classList.remove("invalid");
letter.classList.add("valid");
} else {
letter.classList.remove("valid");
letter.classList.add("invalid");
}

So, My requirement is what ever the way I put my password it should validate the same.

Answer 1

I've created you a working example with 3 restraints: - 2 small letters - 2 capital letters - 2 digits if you need to add a constraint, yjust write a simple regex to match that single constraint, and connect it to the existing if statement via &&. I've used a function to count the number of occurences of regex matches from here.

function testPassword(){
  var pw = document.getElementById("password").value;
  if ( count(pw, /[a-z]/g) > 1 &&
       count(pw, /[A-Z]/g) > 1 &&
       count(pw, /[0-9]/g) > 1 &&
       count(pw,/\W|_/g) > 1                     //special chars
     ){
        
        alert("success")
       
       
       }
        
}

const count = (str,pattern) => {
  const re = pattern
  return ((str || '').match(re) || []).length
}

<input id="password" type="text">
<input type="submit" id="submit" onClick="testPassword()">