What is the difference between async and sync in JavaScript?

What is the difference between async and sync in JavaScript?

In JavaScript, synchronous code runs sequentially, blocking the execution until the current task is completed. Asynchronous code, on the other hand, allows tasks to run in the background, enabling other code to execute without waiting.

Can you give me an example of synchronous code?

Sure! Here's a simple example:

console.log('Start');
console.log('Middle');
console.log('End');

This code runs in order, so 'Start' is logged first, followed by 'Middle', and then 'End'.

And what about an asynchronous example?

An example of asynchronous code is using setTimeout:

console.log('Start');
setTimeout(() => {
  console.log('Middle');
}, 1000);
console.log('End');

Here, 'Start' is logged first, then 'End', and after 1 second, 'Middle' is logged.

Why is asynchronous programming important?

Asynchronous programming is important because it allows for non-blocking operations, improving performance and responsiveness, especially in web applications where tasks like API calls or file reading can take time.