# React.js Hooks

## 1. Why do we use hooks ?

- Reusable logics
- Split code to avoid large components with complicated logics
- Shorter and cleaner code

## 2. Rules of writing hooks:

- Only call hooks from a top level
Which means never calling a hook inside conditional statements and loops

- Only call hooks inside React functions or within another hook

- Always name your custom hooks starting from the "use" keyword

## 3. Some Important built in hooks:

- useEffect()
- useCallback()
- useMemo()
- useReducer()
- useContext()
- etc.

## 4. Custom Hooks:

- Custom hooks is a function that the name start with the word use and can manage life cycle, manage state and call other hooks

- Benefits of writing custom hooks:
+, Reusable code
+, Helps keeps component code neat and clean
+, Abstract operations, an example of declartive programming

## 5. Custom Hooks vs HOCs:

Both of the approach allow us to re-use logics and operations with different react.js components. Hooks are more clean to implement. Here are some differences between the 2: