Immer
Immer is a JavaScript library that simplifies working with immutable state by allowing developers to write code that appears to mutate data directly, while under the hood it produces a new immutable state tree. It uses a copy-on-write mechanism to create a draft of the current state, apply changes to it, and then generate the next immutable state. This approach makes state management more intuitive and less error-prone, especially in applications with complex state structures.
Developers should learn and use Immer when building applications that require immutable state updates, such as those using Redux, React's useState/useReducer, or other state management libraries, to avoid manual deep cloning and reduce boilerplate code. It is particularly useful in scenarios involving nested state objects or arrays, where direct mutations can lead to bugs, and it helps enforce predictable state changes in frameworks like React by ensuring immutability without the cognitive overhead of spread operators or Object.assign.