app.js

const upperSet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
const lowerSet = "abcdefghijklmnopqrstuvwxyz"
const numberSet = "0123456789"
const symbolSet = "~!@#$%^&*()_+/?-"

//selectors
const passBox = document.getElementById("pass-box")
const totalChar = document.getElementById("total-char")
const upperInput = document.getElementById("upper-case")
const lowerInput = document.getElementById("lower-case")
const numberInput = document.getElementById("numbers")
const symbolInput = document.getElementById("symbols")


const getRandomData = (dataSet) => {
    return dataSet[Math.floor(Math.random() * dataSet.length)]
}

const generatePassword = (password = "") => {
    if(upperInput.checked) {
        password += getRandomData(upperSet)
    }
    if(lowerInput.checked) {
        password += getRandomData(lowerSet)
    }
    if(numberInput.checked) {
        password += getRandomData(numberSet)
    }
    if(symbolInput.checked) {
        password += getRandomData(symbolSet)
    }
    if(password.length < totalChar.value) {
        return generatePassword(password)
    }
    
    passBox.innerText = truncateString(password, totalChar.value)
} 


generatePassword();

document.getElementById("btn").addEventListener(
    "click",
    function() {
        generatePassword();
    }

)


function truncateString(str, num) {
    if(str.length > num) {
        let subStr = str.substring(0, num);
        return subStr;
    } 
    else
    {
        return str;
    }
}