Welcome to React Hooks! If you have used React before, you must have heard about Hooks. In this article, we will learn about React Hooks and how to master them in just 30 minutes.
1. What are React Hooks?
React Hooks is a new feature added in the React 16.8 version, allowing you to use the status and other features of React without using Class.
2. Common React Hooks
- useState: Used to add state to the component.
- useEffect: Used to perform side effects, similar to componentDidMount, componentDidUpdate, and componentWillUnmount combined.
- useContext: Used to access the current value of the context.
- useReducer: Manage more complex state with reducers.
- useCallback: Returns a memoized callback.
- useMemo: Returns a memoized value.
- useRef: Returns a ref object.
- useLayoutEffect: Similar to useEffect but it runs synchronously after all DOM mutations. Use it to read layout from DOM and update synchronously.
- useImperativeHandle: Customizes the nature of the instance returned by React.forwardRef.
These Hooks are provided from the React library. Additionally, you can also create your own custom hooks to reuse logic in components.
3. How to use React Hooks?
- useState
Allows you to add state to functional components.
When you want to update the state, use the setCount function (or the name you set when you initialize the hook):
- useEffect
Used to perform side effects like fetching data, manual DOM manipulations, and setting up event listeners.
- useContext
Gives you easy access to context without using Consumer.
- useReducer
Suitable for complex logical states or when the new state depends on the previous state.
- useCallback
Returns a memoized callback. Useful when you’re passing callbacks to child components optimized with React.memo.
- useMemo
Compute some expensive values and only recompute when some dependent values change.
- useRef
Store a reference value without causing a re-render when it changes.
- useLayoutEffect
Works like useEffect but it runs synchronously after all DOM mutations, suitable for reading layout from DOM.
- useImperativeHandle
Use with React.forwardRef to customize the ref that the child component returns.
When using hooks, remember that you should follow the rules of hooks to ensure your application works properly.
4. Tips to Master React Hooks
- Understand each Hook: Start with useState and useEffect before moving on to more complex hooks.
- Practice Regularly: Like learning any other skill, practice is key.
- Read the documentation: React’s official website provides detailed documentation on each Hook.
- See examples: Learn through real-world applications to better understand how to use hooks in real-world situations.
- Todo List Application
- State: Use useState to manage the to-do list.
- Side effects: Use useEffect to save the to-do list to local storage.
- Theme Switcher
- Context: Use useContext to manage switching between light and dark modes.
- Countdown timer
- Use useState to set the initial time and remaining time.
- Use useEffect to decrease the remaining time every second.
- Form Validation
- Use useState to track the value of each input field and the validity state of the form.
- useEffect can be used to display an error message after the user enters data.
- Fetching Data
- Use useState to store fetched data and loading state.
- Use useEffect to perform data fetching when the component is mounted.
- Infinite Scroll
- Combine useState and useEffect to load additional data when the user scrolls to the bottom of the page.
- Custom Hooks
- Once you’re familiar with the basic hooks, you can start creating your own custom hooks. For example, useLocalStorage to read and write data to local storage, or useFetch to make fetch requests easier.
- Todo List Application
It’s important that as you learn through real applications, try building them from scratch. This helps you get a feel for how hooks work and how they interact with each other in a real application.
5. Notes when using React Hooks
- Don’t use Hooks inside loops, conditionals, or functions: Hooks need to be called at the top level of functional components or custom hooks.
- Call Hooks from React functional components: Don’t call hooks from regular JavaScript functions. If you want to reuse logic between components, create a custom hook.
- Call Hooks from custom hooks: This way, you can reuse stateful logic between components. When you write a custom hook, start its name with “use” so you can recognize that it follows the rules of the hook.
- Be careful with Useffect and Dependencies: If you do not provide Array Dependencies for Useffect, it will run after each render.
- Use Usereducer for a complex state: When your state becomes more complicated or you need to handle actions related to the previous state, Usereducer can be a better option than usestate.
- Do not change the value of refs manually: This can cause unexpected behavior. Instead, use the setter function provided by useState or useReducer.
- Be careful with Closure: When you use the internal functions like Useffect, make sure you understand the Closure in Javascript and how it interacts with Hook’s dependencies.
- Test Hooks: Like any other part of your code, make sure you write tests for the logic that uses hooks.
Remember, React Hooks are a powerful and flexible tool, but they also require understanding and care. Working with examples and reading the official React documentation will help you avoid common mistakes.
Conclusion
React Hooks has opened a new era in building user interface with React.
And if you are a developer who wants to apply your knowledge of React Hooks in practice, remember that ITBee Solutions always welcomes potential candidates. Here, you will have the opportunity to participate in projects both domestically and internationally, expand your experience and develop your career. Together, we will not only write code, but also create value and impact the community.
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