jaeapps.blogg.se - Crosscode a promise is a promise 4

Crosscode a promise is a promise 4 code#

What is unique about realms is that they hold all of the necessary information to run JavaScript code. A realm can be roughly thought of as the global object. To better picture this, we can take a closer look at how the realm might be an issue.

The incumbent settings object is tracked in order to ensure that the browser knows which one to use for a given piece of user code. This includes the realm and module map, as well as HTML specific information such as the origin.

Crosscode a promise is a promise 4 code#

If the promise has already been fulfilled or rejected when a corresponding handler is attached, the handler will be called, so there is no race condition between an asynchronous operation completing and its handlers being attached.Īs the () and () methods return promises, they can be chained.Ī settings object is an environment that provides additional information when JavaScript code is running. When either of these options happens, the associated handlers queued up by a promise's then method are called.

rejected: meaning that the operation failed.Ī pending promise can either be fulfilled with a value or rejected with a reason (error).

fulfilled: meaning that the operation was completed successfully.

pending: initial state, neither fulfilled nor rejected.

This lets asynchronous methods return values like synchronous methods: instead of immediately returning the final value, the asynchronous method returns a promise to supply the value at some point in the future.

It allows you to associate handlers with an asynchronous action's eventual success value or failure reason. A Promise is a proxy for a value not necessarily known when the promise is created.