How to Return a Function from Inside a Switch-Case Statement in Swift

Discover how to effectively handle function returns within `switch-case` statements in Swift, ensuring smooth error management in asynchronous operations.
---
This video is based on the question https://stackoverflow.com/q/68086112/ asked by the user 'JacquesNorris' ( https://stackoverflow.com/u/13933359/ ) and on the answer https://stackoverflow.com/a/68098706/ provided by the user 'JacquesNorris' ( https://stackoverflow.com/u/13933359/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to return a function from inside a switch-case statement

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Return a Function from Inside a Switch-Case Statement in Swift

In Swift programming, you may occasionally run into scenarios where you need to manage functions returning values, especially when dealing with conditional logic such as switch-case statements. One common challenge arises when you want to exit early from a parent function based on the result of a nested function within a switch-case structure. In this guide, we will explore the problem and walk you through a clear solution to effectively manage this control flow.

The Problem

Consider a function that checks certain conditions and then decides whether to upload data to a server or use the data locally. The issue occurs when your inner function (e.g., the server upload function) fails and you want to ensure that the parent function does not continue executing subsequent statements. The return statement you might expect to work does not behave as intended due to how control flow is managed inside the nested function.

Here's the Code You're Working With:

[[See Video to Reveal this Text or Code Snippet]]

Output:

[[See Video to Reveal this Text or Code Snippet]]

In the above example, you notice that even when there's a server error, the local data update is still attempted, which is not the desired behavior.

The Solution

Instead of handling errors through completion handlers, a more effective and cleaner approach involves throwing errors directly from your myServerFunction. This allows you to utilize Swift's do-catch blocks to handle error management cleanly.

Step 1: Update myServerFunction to Throw Errors

Here's how you can modify the myServerFunction to throw an error instead of using a completion handler:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Handle the Error in myMainFunction

Now you can catch the error when calling the myServerFunction in the myMainFunction, ensuring that the flow of execution is halted immediately if an error occurs:

[[See Video to Reveal this Text or Code Snippet]]

Final Code Example

Combining both updates, your complete function now looks like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Handling return values from functions within a switch-case statement can be challenging, especially when it comes to managing function execution flow. By throwing errors from your helper functions and handling them with do-catch, not only do you make your code cleaner, but you also significantly improve error management and control flow within your Swift functions.

With these adjustments, you can now confidently manage function returns within nested statements, ensuring that your program behaves as expected in both success and failure scenarios.

Видео How to Return a Function from Inside a Switch-Case Statement in Swift канала vlogize