Javascript Simple Password Strength Checker 2023

This is a very basic password strength checker and is not meant to be used in a real-world application. It only checks for the presence of lowercase and uppercase letters, numbers, and special characters, and checks the password length. A more robust password strength checker would also consider the complexity of the password, such as the use of common words or patterns, and provide a more detailed assessment of the password's strength.

function checkPasswordStrength(password) {
  // Initialize variables
  let strength = 0;
  let hasLowercase = false;
  let hasUppercase = false;
  let hasNumber = false;
  let hasSpecialChar = false;

  // Check for lowercase letter
  if (password.match(/[a-z]/)) {
    hasLowercase = true;
    strength += 1;
  }

  // Check for uppercase letter
  if (password.match(/[A-Z]/)) {
    hasUppercase = true;
    strength += 1;
  }

  // Check for number
  if (password.match(/[0-9]/)) {
    hasNumber = true;
    strength += 1;
  }

  // Check for special character
  if (password.match(/[^a-zA-Z0-9]/)) {
    hasSpecialChar = true;
    strength += 1;
  }

  // Check password length
  if (password.length >= 8) {
    strength += 1;
  }

  // Return password strength
  return strength;
}

To use the function, simply pass a password as a string to checkPasswordStrength() and it will return a number representing the strength of the password, with a higher number indicating a stronger password.

For example:

let password = "mypassword123";
let strength = checkPasswordStrength(password);
// Returns 4