What is async / await in JavaScript?

Before we dive into the nitty-gritty of async and await, let's set the stage. JavaScript, by nature, is non-blocking and asynchronous. This means it doesn't wait around for an operation to complete before moving on to the next one, which is great for keeping things snappy. But what about when you need to perform tasks that depend on the results of previous ones? Enter the world of asynchronous programming — a realm where managing sequences of operations without getting tangled up can be quite the challenge.

Traditionally, we relied on callbacks to handle these scenarios. But callbacks come with their own set of problems, often leading to the infamous "callback hell," where you're stuck in a maze of nested functions, losing sight of clarity and simplicity.

Promises: A Step Forward

Promises stepped onto the scene with a promise (pun intended) of simplifying asynchronous code. They represent a future value — a pledge that at some point, there will be a result, be it a successful one or an error. By using .then() and .catch(), they allow us to write asynchronous code that's more structured and easier to follow than the callback jungle.

However, even with promises, the code can become cumbersome, especially when dealing with complex sequences of async operations. That's where async and await come into play, offering a cleaner and more intuitive way to work with promises.

Understanding async / await

Imagine you could write asynchronous code that looks and behaves like synchronous code. That's the superpower async and await grant you.

The async Function

An async function is a special type of function that simplifies the way we write promise-based code. By adding the async keyword before a function declaration, you transform it into a promise-based powerhouse. Here's the kicker: any async function automatically returns a promise.

async function fetchData() {
  // This function now returns a promise
}

The await Operator

The await operator works hand in hand with async functions. It tells JavaScript to pause the execution of the async function until the promise resolves. The beauty of await is that it unwraps the fulfilled value from the promise, allowing you to handle it as if it were a regular synchronous return value.

async function fetchData() {
  let data = await fetch('https://api.example.com/data');
  console.log(data); // This logs the resolved value of the fetch promise
}

Note how the await keyword halts the execution of fetchData until fetch resolves, giving us clean, synchronous-looking code that's actually asynchronous under the hood.

Handling Errors Gracefully

One of the perks of async and await is how they simplify error handling. By using a try/catch block, you can handle both synchronous and asynchronous errors with the same construct, making your code cleaner and more consistent.

async function fetchData() {
  try {
    let data = await fetch('https://api.example.com/data');
    console.log(data);
  } catch (error) {
    console.error('Oops, something went wrong:', error);
  }
}

Thanks for reading!

Check out our agency site, Cox Code: https://www.coxcode.io

Dialogue with me on X: @benajaero