Catching runtime errors in Javascript - Mini Project: Build & Apply

Catching runtime errors

📖 Scenario: Imagine you are building a simple calculator app that divides two numbers. Sometimes users might enter zero as the divisor, which causes an error. You want to catch this error and show a friendly message instead of crashing.

🎯 Goal: You will create a program that safely divides two numbers and catches any runtime errors using try and catch. If an error happens, it will show a clear message.

📋 What You'll Learn

Create two variables called numerator and denominator with exact values

Create a variable called result and set it to null

Use a try block to divide numerator by denominator and assign to result

Use a catch block to set result to the string 'Error: Cannot divide by zero'

Print the value of result

💡 Why This Matters

🌍 Real World

Handling errors prevents apps from crashing and helps show friendly messages to users.

💼 Career

Error handling is a key skill for developers to build reliable and user-friendly software.

1

Create the numbers to divide

Create a variable called numerator and set it to 10. Create another variable called denominator and set it to 0.

Javascript

// Your code here

Need a hint?

Use const to create the variables with the exact numbers.

2

Prepare a variable to hold the result

Create a variable called result and set it to null.

Javascript

const numerator = 10;
const denominator = 0;
// Your code here

Need a hint?

Use let because result will change later.

3

Use try and catch to divide safely

Write a try block where you divide numerator by denominator and assign it to result. Add a catch block that sets result to the string 'Error: Cannot divide by zero'.

Javascript

const numerator = 10;
const denominator = 0;
let result = null;
// Your code here

Need a hint?

Use throw new Error() inside try when denominator is zero. Catch the error and set result to the error message.

4

Show the result

Write console.log(result) to print the value of result.

Javascript

const numerator = 10;
const denominator = 0;
let result = null;
try {
    if (denominator === 0) {
        throw new Error('Cannot divide by zero');
    }
    result = numerator / denominator;
} catch (error) {
    result = 'Error: Cannot divide by zero';
}
// Your code here

Need a hint?

Use console.log(result) to show the final output.