Gain insights into JavaScript Promises to handle asynchronous events, chain multiple promises, utilize built-in methods, and master async functions with await expressions for efficient event handling.



js.tar.gz

JS promises

promises

Promises are used to deal with event handling and callbacks in asynchronous programming in JavaScript, such as clicks and key presses. Promises allow developers to specify a function to execute at some later point in response to certain events. Promises may also indicate whether a certain code succeeded or failed in performing its assigned job.

In this course, you will learn how to chain different promises, which makes the code easier to understand and debug. Next, you’ll learn built-in methods to monitor and respond to multiple promises executing in parallel. Then, you will cover async functions and await expressions that are often used with promises. Finally, you’ll learn how to track promises when they are rejected without a rejection handler.

Promises are important to understand and debug the code in asynchronous programming. The concepts of JS promises help developers working with Node.js and Deno for event handling and with asynchronous JavaScript APIs.

JavaScript Promises

While `Promise.any()` short-circuits after the first fulfilled promise, we may also want to short-circuit the operation based on the first settled promise, regardless of the outcome. In that case, we can use `Promise.race()`.

# Returning the fastest settling promise as soon as it settles
The `Promise.race()` method provides a slightly different take on monitoring multiple promises. This method also accepts an iterable of promises to monitor and returns a promise, but the returned promise is settled as soon as the first promise is settled. 


Learn how the Promise.race() method returns an appropriate response as soon as any promise settles.

Introduction

Basics of Promises

Chaining Promises

Working with Multiple Promises

Async Functions and Await Expressions

Tracking Down the Unhandled Rejections

Conclusion

The Promise.race() Method

Returning the fastest settling promise as soon as it settles