19 Redux Saga Interview Questions and Answers

Redux Saga is a library used with React and Redux to manage side effects. When applying for a position that uses Redux Saga, it is important to be prepared to answer questions about your experience and knowledge of the library. In this article, we review some of the most common Redux Saga interview questions and provide tips on how to answer them.

Redux Saga Interview Questions and Answers

Here are 19 commonly asked Redux Saga interview questions and answers to prepare you for your interview:

1. What is Redux Saga?

Redux Saga is a library that helps you to manage side effects in your Redux app. Side effects are things like making network requests, accessing the browser’s local storage, or interacting with the browser’s history. With Redux Saga, you can write your side effects as “sagas” that are separate from your Redux reducers. This makes your code more modular and easier to test.

2. Can you explain the difference between an action and a saga in context with Redux Saga?

An action is a plain object that represents an intention to change the state. A saga is a function that is used to take in actions and perform side effects. In other words, an action is something that is done, while a saga is something that watches for actions and does something as a result.

3. How does Redux Saga work?

Redux Saga is a library that helps you to manage side effects in your Redux app. It does this by managing asynchronous code, such as network requests, in a more efficient way. This allows you to better handle errors, and makes your code more readable and easier to maintain.

4. Why do we need to use Redux Saga? Is it mandatory for ReactJS applications?

Redux Saga is a library that helps us to manage side effects in our Redux applications. Side effects can be anything from making an API call to updating the UI. Redux Saga makes it easy to handle these side effects by providing a middleware that can be used to intercept actions and run our side effect code. While Redux Saga is not mandatory for ReactJS applications, it can be very helpful in managing complex side effect logic.

5. What are some of the main features provided by Redux-Saga?

Redux-Saga is a library that aims to make working with asynchronous data in Redux applications easier and more efficient. It provides a number of features, including the ability to easily manage side effects, cancel running tasks, and more.

6. Can you give me a simple example of how Redux Saga works?

Redux Saga is a library that helps you to manage side effects in your Redux app. Side effects are things like making network requests, accessing the browser’s local storage, or interacting with the browser’s history.

In a Redux Saga, you define a function that takes in an action and performs the side effect. This function is called a “saga.” When an action is dispatched, the Redux Saga middleware will call the saga with the action. The saga can then perform the side effect and return a new action.

7. What are the advantages and disadvantages of using Redux Saga?

The main advantage of using Redux Saga is that it makes it easy to manage side effects in your Redux application. This is because Redux Saga uses a declarative approach to managing side effects, which means that you describe what you want to happen, and the library takes care of the rest. The main disadvantage of using Redux Saga is that it can be a bit complex to understand and use, especially if you are not familiar with the concept of generators.

8. How can I check if a generator function has been paused?

You can check if a generator function has been paused by using the yield effect.

9. What’s the best way to test a Redux Saga?

There are a few different ways to test a Redux Saga, but the most common and recommended approach is to use the redux-saga-test-plan library. This library provides a simple and effective way to test sagas by allowing you to mock the Redux store and run tests against your sagas as if they were running in a real application.

10. What’s your opinion on redux-saga vs. redux-thunk?

I believe that redux-saga has a few advantages over redux-thunk. First, redux-saga is less likely to cause race conditions because it uses a declarative approach to asynchronous code that is easier to reason about. Second, sagas are easier to test because they are written as generators. Finally, sagas can be used to handle a variety of side effects in a single place, which can make your code more organized and easier to maintain.

11. What are the differences between redux-saga and redux-observable?

Redux-saga is a library that aims to make side effects in Redux applications easier to manage. It does this by providing a middleware layer that can be used to intercept actions and perform async tasks such as making network requests.

Redux-observable is a library that provides a way to use observables in Redux applications. It can be used to perform async tasks such as making network requests, and also provides a way to cancel those requests if necessary.

12. What are the different ways to handle errors in Redux Saga?

There are a few different ways that you can handle errors in Redux Saga. One way is to use the try/catch method. Another way is to use the takeEvery method. And yet another way is to use the takeLatest method.

13. Do you think that sagas will replace thunks? If yes, then why?

While sagas and thunks both provide a way to perform asynchronous actions in a Redux application, I don’t think that sagas will necessarily replace thunks. Sagas provide a more organized way to manage asynchronous logic, but thunks are still a valid option for simpler applications. In the end, it will come down to personal preference.

14. What are the steps involved in creating a new saga or middleware in Redux Saga?

The first step is to create a generator function. This function will be responsible for handling all of the asynchronous logic in your application. The next step is to create a middleware function. This function will be responsible for intercepting actions dispatched from your Redux store and sending them to your generator function. Finally, you will need to register your middleware function with your Redux store.

15. What are some best practices when developing applications with Redux Saga?

Some best practices when developing applications with Redux Saga include:

– Keep your sagas small and focused on a single task
– Use the takeEvery helper to automatically handle errors
– Use the takeLatest helper to ensure that only the latest action is processed
– Use the put helper to dispatch actions from inside sagas
– Use the call helper to call async functions from inside sagas

16. What happens when a put effect leads to a blocking call?

If a put effect leads to a blocking call, then the Saga will be blocked until the call returns. This can be problematic if the blocking call is taking a long time to complete, as it will prevent the Saga from making any further progress.

17. What’s the best way to cancel running tasks in a Redux Saga?

If you need to cancel running tasks in a Redux Saga, the best way to do it is by using the ‘cancel’ effect. This will allow you to cancel any tasks that are currently running, and it will also prevent any new tasks from starting.

18. What’s the best way to unit test a Redux Saga?

There are a few different ways to unit test a Redux Saga, but the most popular method is to use the redux-saga-test-plan library. This library provides a simple way to test sagas by allowing you to mock the Redux store and run tests against individual sagas.

19. What’s the best way to manage async calls in Redux Saga?

There is no one-size-fits-all answer to this question, as the best way to manage async calls in Redux Saga will vary depending on the specific application. However, some tips on how to best manage async calls in Redux Saga include:

-Using the takeLatest effect to ensure that only the most recent async call is executed
-Using the put effect to dispatch actions that will trigger the async call
-Using the call effect to actually execute the async call
-Using the take effect to wait for the async call to complete before continuing