redux-saga vs redux-thunk: What are the differences?

Introduction

In this article, we will explore the key differences between redux-saga and redux-thunk, two popular middleware libraries for managing async actions in Redux.

1. Data Flow: Redux-saga uses a more declarative approach to handle async actions. It relies on the use of generator functions to yield specific effects that describe how the application should handle async logic. These effects are then interpreted and executed by the redux-saga middleware. On the other hand, redux-thunk uses a more imperative approach, where the async logic is encapsulated within action creators themselves. Thunk functions are used as intermediaries to pause the dispatch of an action and either dispatch a new action or perform some side effect before allowing the original action to proceed.

2. Concurrency and Control Flow: Redux-saga provides better control over the concurrency and control flow of async actions. It allows for complex async flows, such as parallel and sequential processing of actions, using its built-in constructs like take, put, all, and fork. Redux-thunk, on the other hand, can only handle simple async actions and lacks the built-in capabilities to manage complex control flows.

3. Testing: Testing redux-saga can be easier compared to testing redux-thunk. Redux-saga provides a clear separation between the logic and the actual effect, making it easier to write unit tests for the sagas. In contrast, testing redux-thunk involves mocking the behavior of the Redux store and can be more complex due to the tighter coupling between the action creators and the dispatched actions.

4. Handling Timeouts and Delays: Redux-saga has built-in support for handling timeouts and delays. It provides effects like delay and race, which allow for specifying time intervals and handling race conditions between multiple async actions. Redux-thunk does not have built-in support for handling timeouts and delays, requiring developers to handle them manually.

5. Cancellable Actions: Redux-saga allows for cancelling actions during their execution. It provides an cancel effect that can be used to cancel a saga's execution, which in turn cancels the running async action. Redux-thunk does not have native support for cancelling actions, making it harder to manage the cancellation of async actions once they are dispatched.

6. Error Handling: Redux-saga provides a centralized and robust error handling mechanism. It allows for catching errors within sagas using try-catch blocks, and provides takeEvery and takeLatest helpers to handle errors and retries. Redux-thunk, on the other hand, relies on the error handling mechanism of Redux itself, which may not be as flexible or structured as the one provided by redux-saga.

In Summary, redux-saga and redux-thunk differ in their approach to handling async actions, with redux-saga offering a more declarative and powerful solution with better control over concurrency, testing, timeouts, cancellations, and error handling.