Can you modify the state directly in a slice reducer? Why does it work?

Difficulty: 6/10

Immutability in RTK, Proxy-based state mutation, Reducer correctness

Yes, you can modify the state directly inside a slice reducer in Redux Toolkit. This works because Redux Toolkit uses the Immer library internally, which allows writing 'mutating' logic while keeping the state updates immutable under the hood.

How It Works

1
Immer wraps the state object in a proxy, capturing all changes made to it.
2
Instead of mutating the original state, Immer produces a new immutable state based on the changes.
3
This lets you write simpler and more readable reducer code while preserving immutability.

Example: Direct State Updates in a Slice Reducer

Scenario Questions

0-2 years experience

Follow-up Questions