Promises (EN)

Definition

You use Promises in JavaScript to represent asynchronous operations and handle their results or errors. A Promise represents a value that may be available in the future and is in one of three states: pending, fulfilled, or rejected. Methods like .then() allow you to respond to successful operation completion and .catch() to error cases. Promises enable you to structure asynchronous code in a readable and maintainable way and manage complex dependencies between multiple asynchronous operations with .then() or async/await.

Lifecycle

stateDiagram-v2     [*] --> Pending : Creation     Pending --> Fulfilled : resolve()     Pending --> Rejected : reject()     Fulfilled --> [*]     Rejected --> [*] 

In Context

• Typically used together with Callbacks, async/await and Event Loops
• Related to: Callbacks, Observables, Futures
• Example use: API requests, file operations, database queries