9 Advanced JavaScript Promise Patterns Every Developer Should Know

You probably use Promises every day. But these patterns can make your async code cleaner, faster, and much easier to control.

Most developers learn Promises like this:

fetch("/api/users")
.then((res) => res.json())
.then((users) => console.log(users));

And honestly, that’s enough to get started.

But once you start building real applications, things get complicated.

You need to run requests in parallel.

You need to cancel work.

You need to retry failed requests.

You need to handle partial failures.

You need to prevent duplicate API calls.

And sometimes you need to make sure ten different async operations don’t overwhelm your server at the same time.

That’s where Promises become much more interesting.

Here are 9 advanced Promise patterns that I keep coming back to when working with modern JavaScript applications.

1. Run Independent Requests in Parallel

One of the easiest performance improvements is also one of the most commonly missed.