JavaScript Concepts

Asynchronous JavaScript

JavaScript handles asynchronous code using Callbacks, Promises, and Async/Await:

Callback: A function passed as an argument to another function, often used in asynchronous operations.
Promise: An object representing the eventual completion or failure of an asynchronous operation.
Async/Await: A syntactical sugar over Promises for easier handling of asynchronous code.

Examples:


// Callback
function fetchData(callback) {
    setTimeout(() => callback("Data received"), 1000);
}
fetchData(console.log);

// Promise
let promise = new Promise((resolve, reject) => {
    let success = true;
    success ? resolve("Data received") : reject("Error");
});
promise.then(console.log).catch(console.error);

// Async/Await
async function fetchAsyncData() {
    try {
        let result = await promise;
        console.log(result);
    } catch (error) {
        console.error(error);
    }
}
fetchAsyncData();