Скачать или смотреть Understanding Swift If-Else Statements: Resolving the Issue When the Else Block is Never Executed

Discover why your Swift else block isn't executing as expected when dealing with conditional statements and learn how to fix it effectively.
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This video is based on the question https://stackoverflow.com/q/64032385/ asked by the user 'Osvaldo Fernández' ( https://stackoverflow.com/u/7039200/ ) and on the answer https://stackoverflow.com/a/64032494/ provided by the user 'vadian' ( https://stackoverflow.com/u/5044042/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding Swift If-Else Statements: Resolving the Issue When the Else Block is Never Executed

When programming in Swift, you may encounter situations where your code doesn't behave as expected. One common issue developers face is when the else block of an if-else statement never executes, even when you think it should. In this post, we'll go over a specific scenario involving an API response and provide a detailed solution. Let’s unpack the problem and see how to correctly handle it.

The Problem

In your Swift code, you might have implemented a conditional statement to perform specific actions based on the response of an API request. For instance, consider the following code snippet:

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

In this code, it seems like the else block is not being executed when accountRes.complete is false. Let's dig deeper into why this might be happening.

Why Is the Else Block Not Executed?

Common Misunderstanding

The problem often arises from a misunderstanding of how the decoding process works in Swift. If the if condition is reached but the resulting value for accountRes.complete is not true, the else statement should theoretically execute. However, if there's an error during the JSON decoding, the else block gets bypassed entirely because the guard statement would fail.

Decoding Error

If a DecodingError occurs while trying to decode your API response into the expected AccountResponse object, the guard statement prevents any further execution of the code within that scope. Consequently, neither the if block nor the else block would execute.

How to Fix the Issue

To ensure that your code captures decoding errors and allows for proper execution of the else block, follow these steps:

1. Use a do-catch Block

Instead of using try?, you should implement a do-catch block to catch any errors that occur during the decoding process. Here’s how you can modify your code:

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

2. Remove Redundant Checks

In Swift, when you're directly comparing a Boolean value, you can simplify your if statement. Since accountRes.complete is non-optional, you do not need to check for equality with true. Instead, you can write:

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

Conclusion

Mistakes in handling conditional logic in Swift can lead to frustrating bugs, particularly when dealing with API responses. By employing the correct error-handling techniques and simplifying your conditions, you can ensure that your else block executes as expected when accountRes.complete returns false.

By following these adjustments, not only do you resolve the issue of the unexecuted else block, but you also strengthen your coding practices. If you have any more questions about Swift coding or if you've faced similar issues, feel free to share in the comments below!