jQuery deferreds and promises - .then() vs .done()

Understanding jQuery Deferreds and Promises: .then() vs .done()

Have you ever come across the confusion surrounding the usage of .then() and .done() methods in jQuery when working with deferreds and promises? 🤔 It's a common issue that can leave developers scratching their heads, searching for clarity. But worry not - we're here to shed some light on this topic! 💡

The Dilemma: .then() vs .done()

Let's start by addressing the confusion surrounding these two methods. Both .then() and .done() are used for successful callbacks in jQuery. So, naturally, one might wonder: what's the difference? 🤷‍♀️

To get a clearer understanding, let's delve into how these methods work and their specific use cases.

1. .then(): The All-Rounder

.then() is a versatile method that allows you to handle both successful and failed callbacks. It acts as a catch-all for your promises, providing a way to execute code regardless of whether the promise resolves or rejects.

Here's an example to illustrate how to use .then():

doSomething()
  .then(function(result) {
    // Success callback code goes here
  })
  .catch(function(error) {
    // Error callback code goes here
  });

By using .then(), you can handle both successful and failed outcomes within a single code block, making it a powerful and resourceful option. 😎

2. .done(): For Successful Completion Only

On the other hand, .done() is specifically designed to handle successful callbacks only. It ensures that the code inside the .done() block will execute only when the deferred or promise has been successfully resolved.

Here's an example:

doSomething()
  .done(function(result) {
    // Code executed upon successful completion
  });

With .done(), you're explicitly stating that the code inside the block should run only upon successful completion. This can be useful when you solely need to handle successful outcomes. 🌟

Choosing the Right Method

Now that we understand the distinctive features of both .then() and .done(), the question remains: which one should you use? 🤔

Use .then() when:

• You need to handle both successful and failed outcomes within a single code block.

• You want a catch-all solution for your promises.

Use .done() when:

• You only need to handle successful callbacks.

• You want to clearly differentiate between success and failure handlers.

Remember, both methods are powerful tools, and selecting the right one depends on your specific use case and coding style. 💪

Conclusion and Call to Action

And there you have it! We hope this guide has helped you unravel the mystery surrounding .then() and .done() in jQuery deferreds and promises. 😄

Next time you encounter these methods, you'll know exactly when to utilize each one. Feel free to bookmark this article for future reference or share it with your fellow developers who might also struggle with this confusion. Sharing is caring, after all! ❤️

If you have any further questions or if there's another jQuery-related topic you'd like us to explore, drop a comment below. We're always thrilled to engage with our readers and provide valuable insights.

Happy coding! 👩‍💻👨‍💻