Javascript Asynchronous

Asynchronous Javascript

Asynchronous JavaScript refers to the ability of JavaScript code to execute tasks without blocking or delaying other operations. In simple terms, it allows JavaScript to perform multiple actions simultaneously, rather than waiting for each action to finish before moving on to the next.

As it is a single-threaded language, JavaScript executes code in a synchronous manner, where each line of code is executed one after another in the order they appear. This can lead to delays or "blocking" when performing time-consuming tasks, such as fetching data from a server or loading large files.

With asynchronous JavaScript, these time-consuming tasks are handled differently. Instead of waiting for a task to complete before moving on, JavaScript initiates the task and continues executing the next line of code without waiting for the task to finish. Once the task is completed, a callback function is triggered to handle the result or continue with further actions.

This approach allows other parts of the code to continue running while waiting for the task to complete. It improves the overall responsiveness and performance of web applications, as multiple operations can be performed simultaneously.

Common examples of asynchronous operations in JavaScript include making AJAX requests, fetching data from APIs, handling events, and performing animations. By leveraging asynchronous techniques, developers can create smoother, more interactive, and more efficient web applications.

There are three main ways to deal with asynchronous JavaScript to ensure smooth execution and manage the flow of your code. Here are some common approaches:

1. Callbacks: Use callback functions to handle asynchronous results. Pass a function as an argument to an asynchronous function, which will be invoked once the operation is completed. This allows you to continue with further actions or handle the result appropriately.

2. Promises: Promises provide a more structured way to handle asynchronous operations. Promises represent a value that may not be available immediately but will be resolved in the future. You can chain promises using .then() to handle success and use .catch() to handle errors.

3. Async/await: The async and await keywords provide syntactic sugar on top of promises, making asynchronous code look more synchronous and easier to read. The async keyword is used to define an asynchronous function, and await is used to pause the execution of the function until a promise is resolved.

The following has to come under a page called Error Handling in javascript.

Handling errors

To handle errors within our callbacks, the following code introduces two callbacks: success and failure to handle the success and failure cases respectively:-

Input:-

Error Handling

While using the async function, we write the code in a synchronous manner. And we can also use the catch() method to catch the error. The other way we can handle an error is by using a try/catch block. For example,

Input:-

[tryjavascript_Error Handling]

Output:-