React Hooks: Embracing Declarative Programming
My previous post on React Hooks sparked a lively discussion, topping Hacker News and garnering numerous comments. One comment, in particular, stood out – Karen Grigoryan’s insightful observation that Hooks are meant for reusable lifecycle behavior. This realization has transformed my understanding of Hooks and React’s declarative nature.
The Problem with Imperative Code
I initially presented a useFetch example that abstracted away common code for calling a remote API endpoint. However, this implementation was criticized for being too complex and imperative. React is built on declarative principles, where components react to state changes. The original useFetch implementation felt more like an imperative approach, going against React’s grain.
A Declarative Solution
Karen kindly provided a revised useFetch example that simplifies the code and aligns with React’s declarative nature. By using useState and useReducer, we can trigger changes in effects in a declarative way. This approach feels more “React-y” and eliminates the need for forced re-renders.
The Power of useReducer
In the revised useFetch Hook, getFetchResult returns a function that uses dispatch from useReducer to orchestrate lifecycle changes. This approach ensures that components react naturally to state changes, maintaining React’s one-way data flow.
The Stale Closure Problem
One of the challenges with React Hooks is the stale closure problem. When dealing with closures, it’s essential to ensure that the dependency array includes any values from the outer scope that change over time. The react-hooks/exhaustive-deps linting rule helps highlight missing dependencies.
Solving Stale Closures
Dan Abramov’s solution involves storing the callback in a mutable ref. This approach ensures that the latest callback is saved on each render. The useEventCallback Hook from Formik provides a elegant solution to this problem.
Rethinking Hooks
In conclusion, React Hooks require a mindset shift. By embracing declarative programming and aligning with React’s principles, we can unlock the full potential of Hooks. With the right approach, Hooks can become a powerful abstraction for managing state changes and component reactions.