Using promises is an efficient way to handle asynchronous operations. Promises can be used to wrap existing asynchronous operations or as a proxy to handle the eventual success of an asynchronous action.
A promise is an object that represents a commitment and will be fulfilled or rejected in the future. A promise can also be used to aggregate callbacks. This is a clever way to handle asynchronous operations in JavaScript.
A promise can be created using JavaScript’s new Promise constructor. This constructor will wait for all of the promises in the chain to be fulfilled before resolving the chain. The resulting promise is an aggregation of the values from all of the promises that are fulfilled.
A promise can also be used to handle errors. A promise may be rejected after a failed asynchronous operation. For example, a promise can be rejected because a statement is incorrect or a method throws an error. The result may be an error object or an object. A handler can be used to handle a rejected promise.
The microtask of a promise is to use the onResolve function to schedule the onReject function. The onResolve function will schedule the onReject call when the promise is resolved. The onReject function is also optional.
The onResolve function may also be used as a handler for errors. This function may also be used to notify other promises that the onResolve function was called.
The microtask of a promise is to attach a callback to handle the eventual success of an asynchronous operation. The Microtask guide provides instructions on how to do this. It also contains a list of related services and methods.