Скачать или смотреть Resolving the Actions must be plain objects Error in Redux-Observable with RxJS

Learn how to fix the 'Actions must be plain objects' error in Redux-Observable when using RxJS with Firebase and rxfire. This guide breaks down the problem and solution clearly for developers.
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Resolving the Actions must be plain objects Error in Redux-Observable with RxJS

When working with Redux-Observable and RxJS to handle asynchronous actions, you may encounter a frustrating error: Actions must be plain objects. Use custom middleware for async actions. This often leaves developers scratching their heads, especially those new to RxJS or asynchronous action handling in Redux. In this guide, we will explore this error, the problem behind it, and how you can resolve it efficiently.

Understanding the Error

The root of this error stems from misunderstanding how asynchronous behavior is being handled within your epic. In Redux-Observable, an epic listens for actions dispatched to the Redux store and performs side effects, such as making requests to APIs.

The error message implies that your epic is trying to dispatch a non-plain action, likely because of how it’s handling observables and promises. Let's dive into the code snippet you provided to understand what went wrong.

Code Snippet Breakdown

Here's the original code that triggers the error:

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

What's Happening Here?

Async Callback: The flatMap operator wraps the callback with async, turning it into a promise. This means that instead of returning an observable that emits actions, it returns a promise that resolves to an observable.

Observable Handling: Redux-Observable automatically unwraps promises, which results in the observable returned by your epic emitting observables — a situation that causes the aforementioned error.

The Solution: Remove the async Keyword

The simplest way to resolve this issue is to remove the async keyword from your flatMap callback function. Here’s how the revised code looks:

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

Explanation of Changes

By removing the async keyword, the flatMap function is now synchronously returning the observable from the collectionData function:

This observable emits values that will be caught by the map operator.

The map operator is then responsible for returning the plain action fetched from the data.

Summary

In summary, the key to solving the Actions must be plain objects. Use custom middleware for async actions. error lies in ensuring that your Redux-Observable epics are correctly returning observables rather than promises.

Remember:

Remove the async keyword from your callback functions in the epic.

Make sure you return observables directly where expected.

By following the simple adjustment outlined above, you’ll have successfully resolved the issue and be able to enjoy the full functionality of your Redux-Observable epic without further hiccups. Happy coding!