How to make a random password that doesn't start with "-", "

function randomPassword() {
    let length = 15,
        password = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_",
        space = "";
    for (let i = 0, mu = password.length; i < length;   i) {
        space  = password.charAt(Math.random() * mu)
    }
    return space;
}

console.log(randomPassword());

I'm new at javascript. I finally made this code but i don't want it to create a password that starts with "-", "_", "0". How can i do that?

CodePudding user response：

We keep the _, - and 0 away from the character string while we generate the first character for the password. After generating the first character, we add the _, - and 0 back to the character string and generate the rest of the characters for the password.

function randomPassword() {
    let length = 15;
    
    // Initial characters without -, _ or 0
    let characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789";
    
    // Generate first character
    let password = characters.charAt(Math.floor(Math.random() * characters.length   1));
    
    // Add the symbols now
    characters  = "-_0";
    
    // Generate rest
    for (let i = 0; i < length; i  ) {
        password  = characters.charAt(Math.floor(Math.random() * characters.length   1));
    }
    
    // Return
    return password;
}

console.log(randomPassword());

CodePudding user response：

Another approach can be something like this :

function generatePassword() {
  var length = 15,
    charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_",
    retVal = "";
  for (var i = 0, n = charset.length; i < length;   i) {
    let charOne = charset.charAt(Math.floor(Math.random() * n));
    if (i == 0) {
      while (charOne == "-" || charOne == "_" || charOne == "0")
        charOne = charset.charAt(Math.floor(Math.random() * n));
    }
    retVal  = charOne
  }
  return retVal;
}
console.log(generatePassword())

https://jsfiddle.net/40fa5neo/