What are some real-world examples of asynchronous callbacks?

What are some real-world examples of asynchronous callbacks?

Asynchronous callbacks are widely used in programming. For example, in web development, when you make an API call to fetch data, the request is sent, and while waiting for the response, the program can continue executing other code. Once the data is received, a callback function is executed to handle the response.

Can you give me a specific example in JavaScript?

Sure! In JavaScript, the fetch API is a common example. When you call fetch('https://api.example.com/data'), it returns a promise. You can use .then() to specify a callback that will run once the data is fetched, like this:

fetch('https://api.example.com/data')
  .then(response => response.json())
  .then(data => console.log(data));

What about in mobile app development?

In mobile app development, asynchronous callbacks are often used for network requests. For instance, in Swift for iOS, you might use a completion handler in a function that fetches data from a server. This allows the app to remain responsive while waiting for the data.

Are there any downsides to using asynchronous callbacks?

Yes, one downside is callback hell, where callbacks are nested within callbacks, making the code hard to read and maintain. This can be mitigated by using Promises or async/await syntax.