Recalling data user has input and showing if it is a number

Question

This is a two part question, I currently have the below code and I'm trying to have it so that the console will tell me if it is a lower case letter or an upper case letter or of it is a number. I cant seem to get the number.isInteger to work so please tell me where I am going wrong with that.

Also I would like to have it so that there is a call back of what the user entered. So instead of it just saying "This is a upper case letter" I would like it to state "The letter g you entered is lowercase" and vice versa for upperCase and numbers.

Hope that makes sense, please find below my current code. I am new to coding and javascript so please try dumb it down as much as possible for me. Thanks!

Please see below code I currently have:

    let upperLower = prompt("please enter either a uppercase letter, lowercase letter or a number");

if (upperLower == upperLower.toLowerCase()) {

  console.log("The character is lowercase");
}
else if (upperLower == upperLower.toUpperCase()) {
    
    console.log("The character is uppercase");
}
else if (upperLower == Number.isInteger()){

    console.log("This is a number");
}

Answer 1

Or you can check if input converted to number is not a number (isNaN) is false

let upperLower = prompt("please enter either a uppercase letter, lowercase letter or a number");
if (!isNaN(parseInt(upperLower))){

    console.log(upperLower + " is a number");
}
else if (upperLower == upperLower.toLowerCase()) {

  console.log(upperLower + " character is lowercase");
}
else if (upperLower == upperLower.toUpperCase()) {
    
    console.log(upperLower + " character is uppercase");
}