Async/await error handling patterns in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of using try/catch with async/await in Node.js?

To catch and handle errors that occur during asynchronous operations, preventing the program from crashing and allowing graceful error management.

beginner

How does the 'await' keyword affect error handling in asynchronous functions?

The 'await' keyword pauses the function until the Promise resolves or rejects. If it rejects, the error can be caught by a surrounding try/catch block.

intermediate

What is an alternative to try/catch for handling errors with async/await?

Using Promise methods like .catch() after the awaited function call or wrapping the awaited call in a helper function that returns an error and result tuple.

intermediate

Explain the pattern of using a helper function to handle async errors without try/catch.

A helper function wraps a Promise and returns an array like [error, result]. This lets you destructure the result and error without try/catch, simplifying error checks.

beginner

Why is it important to handle errors in async functions in Node.js?

Because unhandled errors can crash the Node.js process, handling errors ensures the app stays stable and can respond properly to failures.

What happens if an awaited Promise rejects and there is no try/catch?

A The error is silently ignored

B The function returns undefined

C The Promise automatically retries

D The Node.js process crashes or the error is unhandled

Without try/catch, a rejected Promise causes an unhandled rejection, which can crash the Node.js process or cause warnings.

Which pattern helps avoid try/catch blocks by returning [error, result]?

A Promise.all()

B Helper function wrapping Promises

C Callback functions

D Event emitters

A helper function can wrap a Promise and return an array with error and result, allowing error handling without try/catch.

Where should you place try/catch blocks when using async/await?

A Around each awaited call that might fail

B Only outside the main function

C Only in synchronous code

D Never, async/await handles errors automatically

Try/catch should wrap awaited calls that might reject to catch errors properly.

What is the benefit of using async/await over .then()/.catch() for error handling?

A Async/await runs faster

B Async/await automatically fixes errors

C Async/await makes code look synchronous and easier to read

D Async/await disables errors

Async/await syntax makes asynchronous code easier to read and write, improving error handling clarity.

How can you handle multiple async errors simultaneously?

A Use Promise.allSettled() and check results

B Use a single try/catch for all Promises

C Ignore errors in parallel calls

D Use synchronous loops

Promise.allSettled() lets you wait for all Promises and see which succeeded or failed, enabling handling multiple errors.

Describe how to use try/catch blocks with async/await to handle errors in Node.js.

Think about how synchronous try/catch works and apply it to async functions.

Explain the helper function pattern that returns [error, result] for async error handling.

Consider how to handle errors without try/catch by returning both error and data.