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.



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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

## Handling multiple promises in order

The `Promise.allSettled()` method is a slight variation of `Promise.all()`; however, it is best suited for when we want to ignore rejections, handle rejections differently, or allow partial success. Here are some common use cases for `Promise.allSettled()`.

## Processing multiple files separately
Usually, we see multiple files that were dependent on one another to succeed. There are also some cases where working on multiple files separately means we don’t need to stop the entire operation if one fails. We go ahead and complete the successful operations and then log the failed ones to retry later. Here’s an example in Node.js:

# Handling multiple promises in order

The `Promise.allSettled()` method is a slight variation of `Promise.all()`; however, it is best suited for when we want to ignore rejections, handle rejections differently, or allow partial success. Here are some common use cases for `Promise.allSettled()`.

# Processing multiple files separately
Usually, we see multiple files that were dependent on one another to succeed. There are also some cases where working on multiple files separately means we don’t need to stop the entire operation if one fails. We go ahead and complete the successful operations and then log the failed ones to retry later. Here’s an example in Node.js:

Discover how Promise.allSettled() processes multiple files separately, calls multiple APIs, and loads web animations simultaneously.

Introduction

Basics of Promises

Chaining Promises

Working with Multiple Promises

Async Functions and Await Expressions

Tracking Down the Unhandled Rejections

Conclusion

When to Use the Promise.allSettled() Method

Handling multiple promises in order

Processing multiple files separately