How to Properly Return API Call Results in React Using Async/Await

Learn how to structure your API calls in React effectively by handling promises correctly, ensuring your functional component can retrieve and render data seamlessly.
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How to Properly Return API Call Results in React Using Async/Await

When building web applications, it's common to encounter scenarios where you need to fetch data from an API and then utilize that data within your React components. One such challenge is ensuring that your API calls return the results properly so that they can be displayed as intended. This post will explore a particular problem faced during user management in a React app and how to resolve the issue of returning API results effectively.

The Challenge: Returning API Call Results

In a recent project using AWS Cognito for user management, a developer was trying to fetch a list of users from their AWS setup. They encountered an issue where the values returned from the API call were undefined, despite the console logging showing a result object with users.

This situation can arise when the asynchronous nature of JavaScript is not handled correctly, especially when working with external APIs. Let’s take a deeper look into the initial setup which led to the dilemma.

Initial Code Breakdown

Below is a simplified overview of the component structure that was being used:

Uses the useEffect hook to call the ListUsers function.

Attempts to set the users' state based on the result from the API call.

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

Configures AWS and attempts to retrieve users from the specified User Pool.

Uses a callback pattern that does not return a value directly to the caller.

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

The issue comes from the fact that the function was not set up to return a value effectively, which caused the call in the container component to receive undefined.

The Solution: Wrapping It in a Promise

To resolve this discrepancy, we can modify the ListUsers function to return a Promise. By doing this, we gain more control over the flow of data and error handling. Here's how to implement the changes:

We will wrap the relevant code in a new Promise, allowing us to explicitly resolve or reject based on the outcome of the API call.

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

With the above change, your container function can remain unchanged since you are already using the await keyword. Here's the relevant part for clarity:

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

Conclusion

By wrapping your API call in a Promise, we can ensure that the results are appropriately returned to the function that needs them. This structure not only allows for a cleaner and more readable codebase but also adheres to better practices in asynchronous programming within React.

Remember that when handling asynchronous operations, clarity in data flow and proper error handling is crucial to develop robust applications. Implement these changes, and you’ll find that fetching and using data from APIs becomes a more seamless part of your React development process.

If you have any questions or run into issues while implementing this solution, feel free to leave a comment!