A promise is an object that represents the eventual completion (or failure) of an asynchronous operation and its resulting value.
Promises are used to handle asynchronous operations in JavaScript, such as fetching data from a server or reading a file.
They provide a cleaner and more readable way to write asynchronous code compared to traditional callback-based approaches.
A promise can be in one of three states: pending, fulfilled, or rejected.
When a promise is pending, it means that the asynchronous operation is still in progress.
When a promise is fulfilled, it means that the asynchronous operation has completed successfully, and the promise returns a value.
When a promise is rejected, it means that the asynchronous operation has failed, and the promise returns an error.
Promises can be chained together using the 'then()' method, allowing for more complex asynchronous workflows.
ES6 introduced native support for promises in JavaScript, making them a standard feature of the language.