How to Properly Return a Value from an async Function in Dart

Learn how to return a string from an async function in Dart while awaiting results from other async calls in Flutter.
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How to Properly Return a Value from an async Function in Dart

As developers venture into the world of Flutter and Dart programming, one common stumbling block emerges: handling async functions correctly. If you're new to Flutter and finding it challenging to return a string from an async function while also awaiting values from other async functions, you're not alone. In this guide, we'll demystify how to tackle this problem effectively.

The Problem: Returning Values from Async Functions

In your current implementation, you're attempting to return a string from an async function, but you're mixing await with .then(), which can lead to unexpected behavior. This pattern can also make your code harder to read and maintain. Let’s take a closer look at the code that caused the confusion:

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When executed, this code can throw an error stating:

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The Solution: Refactoring Code for Clarity

To resolve this issue and to provide a clearer approach, we can refactor your code to utilize await exclusively. This will simplify how asynchronous operations are handled and ensure that we have a definitive return value before the function exits.

Here’s the Refactored Code

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

Key Changes Made

Use of await: Instead of using .then(), we use await for both getUserDetailsFromServer() and getAppointmentsFromServer(cid, isEmployer, rolesList). This makes the flow of the function much clearer and ensures that your code waits for each operation to complete before proceeding.

Removed Unused Variables: The value variable from getUserDetailsFromServer() wasn't used anywhere, so we can safely exclude it to clean up the code.

Conclusion

Your async function should now work as expected, providing a count of shifts assigned to the user without running into errors. If you continue to face issues, please provide a stack trace alongside the full error message.

With this understanding, you will be better equipped to work with async functions in Dart and Flutter. Happy coding!