Async/await error handling patterns in Node.js - Mini Project: Build & Apply

Async/Await Error Handling Patterns in Node.js

📖 Scenario: You are building a simple Node.js app that fetches user data from a mock API. You want to handle errors properly using async/await patterns.

🎯 Goal: Learn how to write async functions with proper error handling using try/catch blocks and helper functions.

📋 What You'll Learn

Create an async function that fetches user data

Add a configuration variable for the API URL

Use try/catch inside the async function to handle errors

Add a helper function to wrap async calls and handle errors gracefully

💡 Why This Matters

🌍 Real World

Handling errors in async functions is essential for building reliable Node.js applications that interact with APIs or databases.

💼 Career

Understanding async/await error handling patterns is a key skill for backend developers working with Node.js to write clean, maintainable, and robust code.

1

Create the async function to fetch user data

Create an async function called fetchUserData that takes a parameter userId and returns a resolved Promise with the string `User data for ${userId}`.

Node.js

// Your code here

Need a hint?

Use the async keyword before the function and return a template string with the userId.

2

Add the API URL configuration variable

Add a constant variable called API_URL and set it to the string 'https://api.example.com/users'.

Node.js

async function fetchUserData(userId) {
    return `User data for ${userId}`;
}

// Your code here

Need a hint?

Use const to declare API_URL with the exact string value.

3

Add try/catch error handling inside the async function

Modify the fetchUserData function to include a try/catch block. Inside try, return the string `User data for ${userId}`. In catch, throw a new Error with the message 'Failed to fetch user data'.

Node.js

async function fetchUserData(userId) {
    // Add try/catch block here
    // Your code here
}

const API_URL = 'https://api.example.com/users';

Need a hint?

Wrap the return statement inside try and handle errors in catch by throwing a new Error.

4

Create a helper function to handle async errors

Create an async function called handleAsync that takes a parameter asyncFunc. Inside, use try/catch to await asyncFunc(). Return an object with { data } if successful or { error } if an error occurs.

Node.js

async function fetchUserData(userId) {
    try {
        return `User data for ${userId}`;
    } catch (error) {
        throw new Error('Failed to fetch user data');
    }
}

const API_URL = 'https://api.example.com/users';

// Your code here

Need a hint?

Use try/catch inside handleAsync to await the function and return an object with either data or error.