JS Defensive Error Handling try catch while loop error

Question

I am writing code to learn defensive error handling in javascript. The program calculates distance, time or speed depending on the user's choice. This bit works fine.

I then tried to add a try catch statement under the prompt-time function and this worked. So I took that code and tried making it into one function rather than typing it out thrice. The idea is that if the user enters something that is not a number or blank the program will keep asking for a number until they do.

But now whenever I enter something that is not a number the while loop does not show the prompt and loops indefinitely. I need a while loop as using an if statement makes the program go on without the correct output.

I am not sure why this is happening.

ask = prompt('Calculate distance(d), time (t) or speed (s)')

function notNumber(input) { 
    while (true)
    try {
             let input = Number(prompt('Enter your ' + input))
             if (isNaN(input) == true || input == "") {
                 throw "Invalid Input";
             }
             return input;
         } 
         
         catch (err) {
             console.log(err);
         }
     }

function promptTime(time) {
    time = Number(prompt('Enter your Time'))

    if (isNaN(time)) {
        notNumber(time)
    }

    return time;
}

function promptSpeed(speed) {
    speed = Number(prompt('Enter your Speed'))

    if (isNaN(speed)) {
        notNumber(speed)
    }

    return speed;
}

function promptDistance(distance) {
    distance = Number(prompt('Enter your distance'))

    if (isNaN(distance)) {
        notNumber(distance)
    }

    return distance;
}

if (ask == 'd') {
    let time = promptTime()
    let speed = promptSpeed()
    distance = time * speed

    if (distance == Number) {
    console.log('Your distance is ' + distance)
    }

    if(isNaN(distance)) {
        notNumber(distance)
    }
}

else if (ask == 't') {
    let distance = promptDistance()
    let speed = promptSpeed()
    time = distance / speed

    console.log('Your time is ' + time)

    if(isNaN(time)) {
        notNumber(time)
    }
}

else if (ask == 's') {
    let distance = promptDistance()
    let time = promptTime()
    speed = distance / time

    console.log('Your speed is ' + speed)

    if(isNaN(speed)) {
        notNumber(speed)
    }
}

else {
    console.log('Please enter a measurement!')
}

Answer 1

Changes: Redefined the promptNumber function from 'input' to a different name ('variable')

Added refer variable to get the name of the desired calculation (time, speed or distance)

Note that I tried calling 'refer' 'name'. But name came up as deprecated.

Got rid of the nested if statements as they are now redundant. For example:

else if (ask == 't') {
    let distance = promptDistance()
    let speed = promptSpeed()
    time = distance / speed

    console.log('Your time is ' + time)

/* Got rid of statements like these
    if(isNaN(time)) {
        notNumber(time)
    }
*/
}

The finalised code is:

ask = prompt('Calculate distance(d), time (t) or speed (s)')

function promptNumber(variable) {
    while (true) {
        try {
            let input = Number(prompt(`Enter a number for ${refer}`));
            if (input == "" || isNaN(input)) {
                throw "Invalid Input";
            }
            return Number(input);

        } catch (err) {
            console.log(err);
        }
    }
}

function promptTime(time) {
    time = Number(prompt('Enter your Time'))
    refer = 'time'

    if (isNaN(time)) {
        time = promptNumber(time)
    }

    else {
        return time;
    }

    return time;
}

function promptSpeed(speed) {
    speed = Number(prompt('Enter your Speed'))
    refer = 'speed'

    if (isNaN(speed)) {
    speed = promptNumber(speed)
    }

    else {
        return speed;
    }

    return speed;
}

function promptDistance(distance) {
    distance = Number(prompt('Enter your distance'))
    refer = 'distance'

    if (isNaN(distance)) {
        distance = promptNumber(distance)
    }

    else {
        return distance;
    }

    return distance;
}

let refer = ''

if (ask == 'd') {
    let time = promptTime()
    let speed = promptSpeed()
    distance = time * speed

    console.log('Your distance is ' + distance)

}

else if (ask == 't') {
    let distance = promptDistance()
    let speed = promptSpeed()
    time = distance / speed

    console.log('Your time is ' + time)
}

else if (ask == 's') {
    let distance = promptDistance()
    let time = promptTime()
    speed = distance / time

    console.log('Your speed is ' + speed)
}

else {
    console.log('Please enter a measurement!')
}