What are the three states of a promise?

In JavaScript, a Promise is an object that represents the eventual completion (or failure) of an asynchronous operation and its resulting value. A Promise can be in one of three states:

1. Pending:

- This is the initial state of a Promise. It indicates that the asynchronous operation has not yet completed, and the final outcome (success or failure) is still unknown. When a Promise is created, it starts in the pending state. During this phase, the Promise is neither fulfilled nor rejected. It's essentially waiting for the asynchronous operation to finish.

2. Fulfilled (Resolved):

- A Promise transitions to the fulfilled state when the asynchronous operation completes successfully. This state indicates that the operation has finished without any errors, and a value is available. The value associated with the fulfilled Promise is often referred to as the "resolved value." You can access this value using the .then() method of the Promise.

3. Rejected:

- A Promise enters the rejected state when the asynchronous operation fails or encounters an error. This state signifies that the operation did not complete successfully, and an error or reason for the failure is available. The reason for the rejection is often referred to as the "rejection reason." You can handle rejected Promises using the .catch() method of the Promise.

Here's a summary of the Promise states:

- Pending: Initial state, neither fulfilled nor rejected.

- Fulfilled: Operation completed successfully, a value is available.

- Rejected: Operation failed, an error or reason is available.

Promises are a fundamental part of asynchronous programming in JavaScript, allowing you to handle asynchronous operations in a more structured and manageable way. They provide a way to avoid callback hell and make asynchronous code easier to read and maintain.

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