Error handling in async/await in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main way to handle errors when using async/await in Node.js?

Use a try/catch block around the await expression to catch and handle errors.

beginner

Why should you avoid using .then() and .catch() with async/await?

Because async/await is designed to work with try/catch for clearer, simpler error handling and better readability.

intermediate

What happens if an error is not caught inside an async function?

The async function returns a rejected Promise, which can cause unhandled promise rejection warnings if not handled elsewhere.

intermediate

How can you handle multiple async operations with error handling?

Use try/catch around each await or use Promise.all with try/catch to handle errors from multiple async calls.

beginner

Show a simple example of error handling using async/await in Node.js.

async function fetchData() {
  try {
    const response = await fetch('https://api.example.com/data');
    const json = await response.json();
    return json;
  } catch (error) {
    console.error('Error fetching data:', error);
  }
}

What keyword is used to wait for a Promise to resolve inside an async function?

A await

B wait

C async

D then

The 'await' keyword pauses the async function until the Promise resolves or rejects.

How do you catch errors when using async/await?

A Using console.log

B Using try/catch blocks

C Using setTimeout

D Using if/else statements

Try/catch blocks are used to catch errors thrown by awaited Promises.

What happens if you forget to use try/catch around an await that rejects?

A The error is ignored silently

B The program automatically retries

C The program crashes immediately

D The error becomes an unhandled promise rejection

Without try/catch, rejected Promises cause unhandled promise rejection warnings.

Which of these is a good practice for handling multiple async calls with error handling?

A Use multiple nested callbacks

B Ignore errors for faster code

C Wrap Promise.all inside try/catch

D Use synchronous loops

Wrapping Promise.all in try/catch lets you handle errors from multiple Promises cleanly.

Can async functions return values directly?

A No, they always return a Promise

B Yes, like normal functions

C Only if you use return await

D Only if you use callbacks

Async functions always return a Promise that resolves to the returned value.

Explain how to handle errors in async/await functions in Node.js.

Think about how you catch errors in synchronous code and apply that to async functions.

Describe what happens if an awaited Promise rejects and there is no try/catch block.

Consider what happens when errors are not caught in normal code.