随机密码生成器显示未定义

Question

Trying to create a random password generator for a class that I am in and for the most part got everything working just fine. Except for the fact that when i try to generate a password it ends up only saying "undefined". The JS is below. Help as soon as possible would be greatly appreciated.

const generateBtn = document.querySelector("#generate");


function writePassword() {
  const password = generatePassword();
  const passwordText = document.querySelector("#password");

  passwordText.value = password;
}


function generatePassword() {

  let lower = "abcdefghijklmnopqrstuvwxyz"
  let lowerArr = lower.split("");
  let upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  let upperArr = upper.split("");
  let num = "0123456789";
  let numArr = num.split("");
  let spec = "!@#$%^&*()_+?<>";
  let specArr = spec.split("");
  let allChars = [];

 
  let password = "";

  let pwlength = prompt("Choose password length: 8-128 characters.");

  if (pwlength < 8 || pwlength > 128) {
    alert("Password must be between defined length.")
    generatePassword()
  }
  if (confirm("Do you want lowercase characters?")) {
    allChars.push(lowerArr);
  }
  if (confirm("Do you want uppercase characters?")) {
    allChars.push(upperArr);
  }
  if (confirm("Do you wamt numeric characters?")) {
    allChars.push(numArr);
  }
  if (confirm("Do you want special characters?")) {
    allChars.push(specArr);
  }
  if (allChars.length === 0) {
    alert("Minimum of one type of character must be chosen");
    generatePassword()
  }
  for (let i = 0; i < pwlength; ++i) {
    let random = Math.floor(Math.random().length);
    password = allChars[random];
  }

  return password;
}



generateBtn.addEventListener("click", writePassword);

Answer 1

At first, instead of pushing the splitted character arrays, just concat them like:

allChars = allChars.concat(lowerArr);

Next:

The Math.floor() function inside the for loop is wrong. You have to combine it with the length of the allChars Array and concatinate the characters to the password variable:

for (let i = 0; i < pwlength; ++i) {
    let random = Math.floor(Math.random() * Math.floor(allChars.length));
    password += allChars[random];
}