What are the best practices for using a reducer in Redux?

What are the best practices for using a reducer in Redux?

When using reducers in Redux, it's important to keep them pure, avoid side effects, and ensure they are easy to test.

Can you explain what you mean by keeping reducers pure?

A pure reducer means that it always returns the same output for the same input and does not modify any external state.

What are some common mistakes to avoid when writing reducers?

Common mistakes include mutating state directly, handling multiple actions in one reducer, and not using switch statements effectively.

How can I test my reducers?

You can test reducers by using unit tests to check if they return the expected state for given actions.