FAQ: Learn JavaScript: Error Handling - Handling with try...catch


#1

This community-built FAQ covers the “Handling with try…catch” exercise from the lesson “Learn JavaScript: Error Handling”.

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This exercise can be found in the following Codecademy content:

Web Development

FAQs on the exercise Handling with try…catch

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#2

So the main point of the try…catch in this exercise, is to demonstrate that by catching the error, you are still able to continue running your code to the end?


#3

That’s correct. Instead of letting the interpreter handle the error, we do that in our code and flow is unbroken.

let u;
let e = "";
do {
    u = prompt(e + "Enter a number between 0 and 100");
    try {
        if (u > 0 && u < 100) {
            u = +u;
            break;
        }
        if (u === null) {
            break;
        }
        throw 'anException';
    }
    catch(error) {
        e = "Try again... "
    }
} while (true);

There are no real exceptions in this code so we have to throw one. Since JS is loosely typed, number operations either result in a number, or NaN and JS churns along either way.

When using prompt() we need to test for null to see if the Cancel button was clicked or the Esc key pressed.

There are of course many ways to approach this problem with exception handling. This is by no means a conclusive example.