Mastering React Query: How to Handle Nested and Conditional Chained API Calls

Learn how to implement efficient nested and conditional chained API calls using `React Query` with practical examples and solutions.
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Mastering React Query: How to Handle Nested and Conditional Chained API Calls

In the world of modern web applications, managing API calls efficiently is crucial for maintaining performance and user experience. One common scenario developers encounter is the need to make nested or conditional chained API calls. This can be particularly challenging when working with React Query. In this post, we'll explore the problem and provide a clear, structured solution to implement nested API calls optimally.

The Problem: Nested and Conditional Chained API Calls in React Query

Imagine you have an application that needs to fetch car details based on the car's make. For example, if the car is a Honda, you would need to call the Honda API first, and based on the response, you’d call another API to get detailed information about that car. Similarly, this logic applies to Tesla cars as well. However, one of the limitations in React is that hooks can only be called at the top level of a React function component or custom hook, making it challenging to structure your API calls conditionally.

Here’s a simplified representation of what you might want to achieve:

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

However, calling hooks within conditional statements (like if) directly is not permitted. This limitation can lead to complexities when trying to implement various API calls based on dynamic conditions. So, what’s the solution?

The Solution: Using the Enabled Flag

Instead of directly calling hooks conditionally, we can utilize the enabled flag provided by React Query. This flag allows you to control when a particular query should be executed. Here’s how you can implement this neatly without breaking the rules of hooks:

Step-by-Step Implementation

Always Invoke the Hooks: Call your API hook for both Honda and Tesla regardless of the condition.

Use the Enabled Flag: Use the enabled flag to only allow the relevant API call to proceed based on the car's make.

Handle the Responses: Check for errors in your first API responses and return them if they occur. Otherwise, proceed to fetch car details.

Here's the revised version of our getCarDetails function that employs this approach:

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

Important Considerations

Return Custom Objects: Rather than returning the response directly, which could lead to confusion when errors occur, consider returning a custom object that encapsulates data, error, and loading states. For example:

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

Naming Conventions: Since getCarDetails is a custom hook utilizing hooks inside it, remember to prefix the function name with use, i.e., useCarDetails.

Conclusion

Handling conditional and nested API calls in React Query can initially seem daunting due to the constraints posed by hooks. However, by utilizing the enabled flag and structuring your API calls properly, you can create efficient data-fetching logic that enhances the responsiveness of your application. By following the approach outlined above, you can effectively manage multiple API responses while maintaining clarity and control over your data flow.

Next time you find yourself needing nested API calls in React, remember these strategies, and your codebase will be much cleaner and more manageable.