Promise in javascript

A Promise in JavaScript is an object that represents the result of an asynchronous operation.

It helps handle tasks like:

• API calls

• File loading

• Database requests

• Timers (setTimeout)

Instead of waiting for the task to finish, JavaScript continues running other code.

Promise States

A Promise has 3 states:

• Pending → Initial state

• Resolved / Fulfilled → Operation successful

• Rejected → Operation failed

Promise Methods

Method and Purpose

.then() -> Runs when promise is successful

.catch() -> Runs when promise fails

.finally() -> Runs always

output

Callback Hell.

output