Error handling in async/await in Node.js - Mini Project: Build & Apply

Error handling in async/await

📖 Scenario: You are building a simple Node.js app that fetches user data from a fake API. Sometimes the API might fail, so you need to handle errors properly to keep your app running smoothly.

🎯 Goal: Learn how to use async functions with await and handle errors using try/catch blocks in Node.js.

📋 What You'll Learn

Create an async function to fetch user data

Add a helper variable to simulate API success or failure

Use try/catch to handle errors inside the async function

Call the async function and handle the final result or error

💡 Why This Matters

🌍 Real World

Handling errors in async/await is essential when working with APIs or any asynchronous operations in Node.js to keep applications stable and user-friendly.

💼 Career

Understanding async error handling is a key skill for backend developers, API developers, and anyone working with asynchronous JavaScript in Node.js environments.

1

Create the async function to fetch user data

Write an async function called fetchUserData that returns a promise resolving to the object { id: 1, name: 'Alice' }.

Node.js

# Your code here

Need a hint?

Use the async keyword before the function and return the user object directly.

2

Add a helper variable to simulate API success or failure

Create a variable called apiSuccess and set it to false to simulate an API failure.

Node.js

async function fetchUserData() {
    return { id: 1, name: 'Alice' };
}

# Your code here

Need a hint?

Use const apiSuccess = false; to create the helper variable.

3

Use try/catch inside the async function to handle errors

Modify the fetchUserData function to use a try/catch block. Inside try, if apiSuccess is false, throw an error with the message 'API request failed'. Otherwise, return the user object { id: 1, name: 'Alice' }. In catch, rethrow the error.

Node.js

async function fetchUserData() {
    // Your code here
}

const apiSuccess = false;

Need a hint?

Use try to check apiSuccess. Throw an error if false. Catch the error and rethrow it.

4

Call the async function and handle the result or error

Write an async function called main that calls fetchUserData using await inside a try/catch block. In try, assign the result to a variable user. In catch, assign the error message to a variable errorMessage. Then call main().

Node.js

async function fetchUserData() {
    try {
        if (!apiSuccess) {
            throw new Error('API request failed');
        }
        return { id: 1, name: 'Alice' };
    } catch (error) {
        throw error;
    }
}

const apiSuccess = false;

// Your code here

Need a hint?

Use async function main() with try/catch. Await fetchUserData(). Handle error message in catch. Call main() at the end.