Understanding Promises in JavaScript

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A promise in JavaScript represents the eventual completion of data, unlike regular variables or function returns. It is like an IOU, committing to providing data in the future or failing to do so (rejecting). So, a promise is a future agreement for data retrieval.

In this 3-course series, Scott and Wes serve up some JavaScript Promises treats. In part 1, they unravel the concept of promises and delve into common examples of their usage, from creating and waiting on promises, to database queries and user permissions.

Show Notes

00:00 Welcome to Syntax!
01:27 Brought to you by Sentry.io.
02:32 What is a promise?
Promise mdn web docs.
03:27 Common examples of promises.
- 03:45 A fetch call to an API returns a promise.
- 05:54 A database query or Insert command
- 07:18 A request for user permissions.
- 07:37 A wait function.
08:08 Resolve or rejecting promises.
09:33 Creating promises.
- 09:46 New promise.
- 11:09 Promise.withResolvers().
- 11:37 An async function.
14:34 Waiting on a promise.
- 15:09 .then().
- 16:50 Await.
- 17:44 Why use one wait method over the other?