AJAX - Async and Await with AJAX Requests

Async and Await are modern JavaScript features introduced to simplify asynchronous programming. Before Async and Await, AJAX operations were mainly handled using callbacks or Promises, which often made code difficult to read and manage. Async and Await make asynchronous AJAX requests look and behave like normal synchronous code, improving clarity and maintainability.

An asynchronous operation is one that takes time to complete, such as requesting data from a server. While the request is being processed, the browser continues executing other tasks instead of waiting. AJAX works asynchronously, and Async and Await help manage this process in a cleaner way.

The keyword async is used before a function declaration to indicate that the function will perform asynchronous operations. An async function always returns a Promise automatically, even if a normal value is returned.

The keyword await is used inside an async function. It pauses the execution of the function until the Promise is completed. This allows developers to write code step by step instead of using multiple nested callbacks.

Example using Fetch API with Async and Await:

async function getData() {
    try {
        let response = await fetch("https://api.example.com/data");
        let data = await response.json();
        console.log(data);
    } catch(error) {
        console.log("Error occurred:", error);
    }
}

getData();

Explanation of the example:

The async keyword defines the function as asynchronous.
The await keyword waits for the server response before moving to the next line.
The fetch function sends an AJAX request to the server.
The response is converted into JSON format using response.json().
The try and catch block handles errors safely.

Advantages of Async and Await:

It makes AJAX code easier to read and understand.
It reduces callback nesting problems.
Error handling becomes simpler using try and catch blocks.
Code execution appears sequential even though it is asynchronous.

Limitations:

Await can only be used inside async functions.
If used incorrectly, it may block execution inside that function until completion.

Async and Await are now widely used in modern web development because they provide a cleaner and more efficient way to perform AJAX operations.