Solving async await Issues in Vue 3 Composable Functions

Learn how to effectively handle asynchronous operations in Vue 3 composable functions using alternative approaches, specifically when `async await` isn't working as expected.
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Troubleshooting async await in Vue 3 Composable Functions

Developing applications with Vue 3 brings a host of compelling features, including its straightforward handling of asynchronous operations through async and await. However, sometimes developers encounter issues where these keywords don’t function as intended, especially when working with composable functions. In this post, we'll explore a common problem related to using async await in a composable function and offer a solution that sidesteps the issue effectively.

The Problem: async await Not Working as Expected

In a recent project, a developer encountered problems while attempting to implement a file download feature. The core functionality was encapsulated in a composable function, and the goal was to indicate a loading state while the download was in progress. Here is a simplified version of the setup:

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

The intent was for the loading state to trigger an indicator while the download operation was in progress. Yet, the developer faced a challenge—the await keyword would not work properly in the composable function, leading to unexpected behavior with the loading state.

An Innovative Solution: Refactor Without async await

Rather than letting this issue stall progress, the developer considered refactoring the useOnDownload function to handle loading directly. The solution involved passing the loading state reference as a parameter, thus allowing the function to manage loading states more effectively.

Here’s how the refactored useOnDownload function looks:

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

Breakdown of the Solution

1. Refactor Your Function

By passing the loader reference to useOnDownload, the function can modify the loading state directly. This change also promotes reusability since the function can now manage loading in various components without the async await hassle.

2. Check for Undefined Loader

The function checks if the loader reference is defined before attempting to set its value. This ensures that you avoid potential runtime errors if loader is not passed.

3. Manage Loading State

4. Error Handling

In the catch block, identical cleanup for the loading state is performed, ensuring that users are never left in the dark if an error occurs.

Conclusion

Handling asynchronous operations in Vue 3 could get tricky, especially when diving into composable functions with async await. By refactoring the approach and shifting how we manage loading states, developers can work around issues while simplifying their codebase. This brings not only clarity and reusability to functions but also a smoother user experience during asynchronous operations.

If you find yourself grappling with async await in composable functions, consider this method as a viable alternative in your Vue 3 applications.