Understanding JavaScript Promises

Introduction to Promises

JavaScript promises provide a powerful way to handle asynchronous operations. A promise represents a value that may be available now, in the future, or never. Promises are useful for better handling of callbacks and provide a cleaner, more readable approach to managing asynchronous code.

Why Use Promises?

Promises simplify handling asynchronous code in a more predictable manner. They help in avoiding "callback hell" and make code easier to manage, especially when dealing with multiple asynchronous operations.

States of a Promise

• Pending: Initial state, neither fulfilled nor rejected.
• Fulfilled: The operation was completed successfully.
• Rejected: The operation failed.

Using Promises

let promise = new Promise(function(resolve, reject) {
    // asynchronous operation
    let success = true;
    if (success) {
        resolve("The operation was successful!");
    } else {
        reject("The operation failed.");
    }
});

promise.then(function(result) {
    console.log(result); // The operation was successful!
}).catch(function(error) {
    console.log(error); // The operation failed.
});