Скачать или смотреть How to Dispatch an Action at the End of an Epic with Redux-Observables

Discover how to dispatch an additional action at the end of an epic using Redux-Observables, including practical code snippets and explanations.
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Disposing an Action at the End of an Epic with Redux-Observables

When working with Redux-Observables in a Redux application, handling side effects effectively is crucial. One common scenario is requiring two actions to be dispatched as a result of a single event. In this guide, we’ll explore how you can dispatch an additional action at the end of an epic, specifically to set notifications while handling updates.

Understanding the Problem

Suppose you have an epic responsible for updating an applicant's information in your application. Upon successful completion of the update, you would like to dispatch another action to set a notification with relevant details such as the status of the operation and informational messages received in the response.

This might leave you wondering: How do you integrate dispatching that second action seamlessly within an existing epic?

The Solution: Modifying the Epic

To achieve the objective of dispatching another action within your epic, we can leverage the mergeMap operator. This approach allows for multiple actions to be emitted in response to an incoming action. Let’s take a look at how this can be done with code:

Step 1: Update the Epic

Here’s an adapted version of your updateApplicantEpic that includes dispatching the setNotification action:

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

Step 2: Handle the Notification

In the code above, notice how we are dispatching both updatedApplicant and setNotification within the mergeMap function. This allows both actions to be processed in the order they are defined:

updatedApplicant(response.status, action.applicant): This action updates the applicant with the given details.

setNotification(response): This action sets a notification using the response details.

Step 3: Create the setNotification Action

Next, you'll need to ensure that you have a properly defined action creator for setNotification. Its TypeScript signature might look like this:

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

Where Response is a type representing the response structure that includes the necessary details like status and message.

Conclusion

By adapting your epic to include an additional action dispatch, you not only make your Redux state management more robust but also provide users with timely feedback about operations in your application. Using mergeMap, you can easily handle multiple emissions from a single input event, allowing your application to remain responsive and user-friendly.

Takeaway

Deploying this method effectively facilitates future implementations where multiple actions may need to respond dynamically to a single source action.

Feel free to integrate this approach into your own Redux-Observable flows and enjoy greater flexibility in handling side effects!