Calling a function in an if-else statement

Question

I'm trying to get the add() function to calculate in the if-else statement and not the line commented out for part of an assignment but I'm not sure how to get it to show the result in a new window.

function add(){
   return +num1 + +num2
};

const num1 = window.prompt("Enter a number: ");
const operatorInput = window.prompt("Do you want to add, subtract, multiply, or divide?");
let num2;

if (operatorInput === "add" || operatorInput === "Add") {
    num2 = window.prompt("Second Number: ");
    // add()
    // let sum= parseInt(num1) + parseInt(num2)
    // alert(num1 + " " + "+" + " " + num2 + " " + "=" + " " + add());
    alert(`${num1} + ${num2} = ${add()}`);
};

Answer 1

Not sure if that's what you need.

var num1 = parseFloat(window.prompt("Enter a number: "));
var operatorInput = window.prompt(
    "Do you want to add, subtract, multiply, or divide?"
);
while (
    operatorInput.toLowerCase() != "add" &&
    operatorInput.toLowerCase() != "multiply" &&
    operatorInput.toLowerCase() != "divide" &&
    operatorInput.toLowerCase() != "subtract"
) {
    alert("Invalid Input! Please try again");
    operatorInput = window.prompt(
        "Do you want to add, subtract, multiply, or divide?"
    );
}
var num2 = parseFloat(window.prompt("Second Number: "));
var resultWindow = window.open("", "Result Window", "width=200,height=200");
if (operatorInput.toLowerCase() == "add")
    resultWindow.document.write(
        `<p>${num1 + " " + "+" + " " + num2 + " " + "=" + " " + (num1 + num2)
        }</p>`
    );
else if (operatorInput.toLowerCase() == "multiply")
    resultWindow.document.write(
        `<p>${num1 + " " + "*" + " " + num2 + " " + "=" + " " + num1 * num2
        }</p>`
    );
else if (operatorInput.toLowerCase() == "divide")
    resultWindow.document.write(
        `<p>${num1 + " " + "/" + " " + num2 + " " + "=" + " " + num1 / num2
        }</p>`
    );
else
    resultWindow.document.write(
        `<p>${num1 + " " + "-" + " " + num2 + " " + "=" + " " + (num1 - num2)
        }</p>`
    );

You should be careful with using new windows to display information, it's not recommended and many browsers now adays automatically blocks these actions and consider them as spam popup windows if they're directly invoked by javascript. If the results are not being shown for you make sure to allow your browser to allow popups from the link you're displaying it from.