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How to Use React Hooks for More Efficient Coding

React Hooks, introduced in React 16.8, represent a significant shift in how we write React code. They allow us to use state and other React features without writing a class, making our code more readable and easier to understand. Hooks are functions that let you “hook into” React state and lifecycle features from function components. They do not work inside classes; instead, they let you use React without classes.

This article aims to provide a thorough understanding of React Hooks. We’ll delve into the basics of React Hooks, discuss their key advantages, and provide practical guides on how to use them. The aim is to empower you with the knowledge and skills to leverage React Hooks effectively in your projects. By the end of this article, you should have a solid grasp of React Hooks and be able to confidently apply them in your day-to-day coding tasks.

What are React Hooks?

React Hooks are functions that allow developers to use state and other React features in functional components. Introduced in React 16.8, hooks provide a more expressive way to reuse component logic, manage stateful logic, and handle side effects within react function components. Before hooks, developers primarily used class components to manage state and lifecycle methods, but hooks bring a more functional and modular approach to React development.

Detailed Explanation of How React Hooks Work:

useState Hook:

  • The useState hook is one of the fundamental hooks that enables functional components to manage state.

  • It takes an initial state as an argument and returns an array with two elements: the current state and a function to update that state.

  • Example:

    const [count, setCount] = useState(0);

useEffect Hook:

  • The useEffect hook is used to handle side effects in functional components, such as data fetching, subscriptions, or manually changing the DOM.

  • It runs after every render and can perform cleanup actions when the component is unmounted.

  • Example:

    useEffect(() => { // Side effect code here return () => { // Cleanup code here }; }, [dependency]);

Other Hooks (useContext, useReducer, useRef, etc.):

Each hook serves a specific purpose, providing a clean and concise way to manage different aspects of a component’s behavior.

  • For example, useContext allows components to subscribe to React context without introducing nesting, while useReducer facilitates state management in a more controlled and predictable manner.

  • useCallback: Returns a memoized version of a callback to prevent unnecessary re-renders.

  • useMemo: Returns a memoized value to optimize performance.

  • useRef: Returns a mutable ref object whose .current property is initialized with the passed argument.

  • useLayoutEffect: Fires synchronously after all DOM mutations, similar to useEffect.

  • useDebugValue: Helps to display a label in React DevTools for custom hooks.

You can check out this video to learn more about React hooks

Understanding these Hooks is crucial for mastering React Hooks. In the following sections, we will dive deeper into each of these Hooks, providing practical examples and best practices for their usage.

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Key Advantages of Using React Hooks

React Hooks offer several key advantages that enhance the development process and the quality of the final product:

Simplified Code:

One of the primary benefits of using React Hooks is the simplification of the codebase. Hooks eliminate the need for class components, which often require more boilerplate code and can be harder to read and understand. With Hooks, developers can write cleaner, more intuitive code. For instance, a simple counter component implemented with Hooks would look like this:

function Counter() {
   const [count, setCount] = React.useState(0);

   function incrementCount() {
       setCount(count + 1);
   }

   return (
       // JSX goes here
   );
}

This is compared to a similar component implemented with class components, which would require more lines of code and a less straightforward structure.

Improved Reusability:

React Hooks make it easier to reuse stateful logic across components. With custom hooks, developers can extract component logic into reusable functions. This promotes cleaner, more modular code, and reduces duplication. For example, a custom hook for fetching data might look like this:

function useFetch(url) {
   const [data, setData] = React.useState(null);
   const [loading, setLoading] = React.useState(true);

   React.useEffect(() => {
       async function fetchData() {
           const response = await fetch(url);
           const data = await response.json();
           setData(data);
           setLoading(false);
       }
       fetchData();
   }, [url]);

   return { data, loading };
}

This custom hook can then be used in any component that needs to fetch data, reducing code duplication.

  1. Easier Testing and Debugging: Functional components that use Hooks are generally easier to test and debug than class components. Since Hooks promote separation of concerns and a more functional programming style, developers can write more predictable and testable code 1.

  1. Reduced Bundle Size: By using functional components with Hooks instead of class components, developers can reduce the overall size of their application bundle. This can lead to faster load times and improved performance for users.

  2. Reduced Prop Drilling: One of the common challenges in React development is prop drilling, where props have to be passed through multiple layers of components. React Hooks, particularly the useContext hook, addresses this issue by allowing components to subscribe to a context directly. This eliminates the need to pass props down through intermediate components, making the codebase more maintainable and improving component encapsulation.

  3. Improved Performance Through Memoization: React Hooks such as useMemo and useCallback contribute to improved performance by memoizing values and functions. Memoization ensures that expensive calculations or functions are only recomputed when necessary, preventing unnecessary renders and optimizing the application’s overall performance.

  4. Simplified State Management: React Hooks, particularly the useState and useReducer hooks, simplify state management in functional components. The concise syntax and ease of use contribute to cleaner and more readable code compared to class components. Developers can declare state variables and update functions directly within the functional component, eliminating the need for complex class structures and the use of this.setState.

How to Use React Hooks

In this section, we’ll cover some of the commonly used hooks:

useState: Managing State in Functional Components

The useState hook is fundamental for managing state in functional components. It returns an array with the current state value and a function to update that state. Here’s an example of how to use useState:

import { useState } from 'react'

function App() {
 const [count, setCount] = useState(0)

 return (
   <div className="App">
     <p>Count is: {count}</p>
     <button onClick={() => setCount(count+1)}>Add 1</button>
     <button onClick={() => setCount(count-1)}>Decrease 1</button>
   </div>
 )
}

export default App

In this example, useState is called with the initial state (0). It returns an array with two elements: the current state (count) and a function to update it (setCount). When setCount is called, the component re-renders with the new state.

useEffect: Handling Side Effects in Functional Components

The useEffect hook lets you perform side effects in function components. Side effects could be data fetching, subscriptions, or manually changing the DOM. Here’s an example of how to use useEffect:

import { useState, useEffect } from "react";

function Counter() {
   const [count, setCount] = useState(0);

   useEffect(() => {
   	console.log(`Count is ${count}`);
   });

   return (
       <div>
       Current count: {count}
           <div>
               <button onClick={() => setCount(count + 1)}>Add to cart</button>
               <button onClick={() => setCount(count - 1)}>Remove from cart</button>
           </div>
       </div>
   );
}

In this example, useEffect runs after every render. The function passed to useEffect will run after the render is committed to the screen. Think of effects as an escape hatch from React’s purely functional world into the imperative world.

useContext: Accessing Context in Functional Components

The useContext hook is a built-in hook that allows you to access the value of a context. It accepts a context object as its argument and returns the current value of that context. When the value of the context changes, the component re-renders. Here’s an example:

import React, { createContext, useState, useContext } from "react";

// Create a context
const ThemeContext = createContext(null);

// Provide the context value
const ThemeProvider = ({ children }) => {
 const [theme, setTheme] = useState("light");

 return (
   <ThemeContext.Provider value={theme}>
     {children}
   </ThemeContext.Provider>
 );
};

// Consume the context value
const ThemeConsumer = () => {
 const theme = useContext(ThemeContext);

 return <div>The current theme is {theme}</div>;
};

export default () => (
 <ThemeProvider>
   <ThemeConsumer />
 </ThemeProvider>
);

In this example, ThemeContext is created using createContext(). ThemeProvider provides the current theme value, and ThemeConsumer consumes the theme value.

useReducer Hook

The useReducer hook is another built-in hook that is usually preferable to useState when you have complex state logic that involves multiple sub-values or when the next state depends on the previous one. useReducer also lets you optimize performance for components that trigger deep updates because you can pass dispatch down instead of callbacks. Here’s an example:

import React, { useReducer } from 'react';
// initial value

const initialState = { count: 0 };

function reducer(state, action) {
  switch (action.type) {
    case "increment":
      return { count: state.count + 1 };
    case "decrement":
      return { count: state.count - 1 };
    default:
      throw new Error();
  }
}

export default function App() {
  const [state, dispatch] = useReducer(reducer, initialState);

  return (
    <>
      Count: {state.count}
      <button onClick={() => dispatch({ type: "decrement" })}>-</button>
      <button onClick={() => dispatch({ type: "increment" })}>+</button>
    </>
  );
}

In this example, useReducer is used to manage the count state. The reducer function handles the actions and returns the new state.

useMemo Hook

The useMemo hook returns a memoized value. Pass a “create” function and an array of dependencies. useMemo will only recompute the memoized value when one of the dependencies has changed. This optimization helps to avoid expensive calculations on every render. Here’s an example:

import React, { useMemo } from 'react';

function MyComponent({ list }) {
 const sortedList = useMemo(() => {
   console.log('Sorting...');
   return list.sort((a, b) => a - b);
 }, [list]);

 return (
   <ul>
     {sortedList.map(item => (
       <li key={item}>{item}</li>
     ))}
   </ul>
 );
}

In this example, useMemo is used to sort a list. The sorting operation is only performed when the list changes.

Building a Custom React Hook

Creating custom hooks in React allows you to abstract component logic into reusable functions. This means you can share stateful behavior between components, keeping your code DRY (Don’t Repeat Yourself) and improving maintainability. Let’s see how to build a custom hook.

Why Build Custom Hooks?

Custom hooks can encapsulate complex logic, making it easier to understand and reuse. They can also help to keep components clean and focused on rendering UI. For example, consider a complex component that manages a lot of local state in an ad-hoc way. Instead of using useState to manage this state, you might prefer to write it as a Redux reducer. This approach makes the update logic easier to test and scale, and it also allows you to take advantage of the benefits of using React local state 1.

Building a Custom Hook

Let’s start with a simple example of a custom hook that fetches data from an API. This custom hook will use the fetch function to retrieve data, and it will return the data and a loading status.

import { useState, useEffect } from 'react';

function useFetch(url) {
 const [data, setData] = useState(null);
 const [loading, setLoading] = useState(true);

 useEffect(() => {
   async function fetchData() {
     const response = await fetch(url);
     const data = await response.json();
     setData(data);
     setLoading(false);
   }
   fetchData();
 }, [url]);

 return { data, loading };
}

In this example, useFetch is a custom hook that takes a URL as its argument. It uses useState to initialize the data and loading states, and useEffect to fetch the data when the component mounts or when the URL changes. The hook returns an object containing the data and loading status.

Check out this 10 minutes video on custom hooks to learn more about it

In the following sections, we will discuss best practices for creating custom hooks, and then move on to considerations for when to use React Hooks.

When to Use React Hooks

React Hooks are a powerful tool that can simplify your code and make it more efficient. However, like any tool, they are not always the right solution for every situation. Understanding when to use React Hooks can help you make the most of their benefits.

Scenarios Where Hooks Are Beneficial

  1. Managing Local State: If your component needs to manage its own state, React Hooks can be a great choice. For example, if you have a form component that needs to track its own input values, you can use the useState hook to manage these values.

  1. Performing Side Effects: If your component needs to perform side effects, such as fetching data, setting up subscriptions, or updating the DOM, you can use the useEffect hook.

  1. Accessing Context Values: If your react components needs to access values from a context, you can use the useContext hook.

  1. Handling Complex State Logic: If your component has complex state logic, such as when the next state depends on the previous one, you can use the useReducer hook.

  1. Optimizing Performance: If your component performs expensive computations, you can use the useMemo hook to avoid recalculating these values on every render.

  1. Reusing Component Logic: If you find yourself repeating the same logic across multiple components, you can extract this logic into a custom hook.

When Not to Use Hooks

While Hooks are a powerful feature, they are not always the right choice. Here are some situations where Hooks may not be the best fit:

  1. Class Components: Hooks are designed to work with functional components. If you’re working with class components, you won’t be able to use Hooks.

  1. Simple Components: If your component doesn’t need to manage its own state or perform side effects, using Hooks may be overkill. In these cases, a simple functional component might be sufficient.

  1. Legacy Codebases: If you’re working with older codebases that haven’t been upgraded to support Hooks, it might not be feasible to introduce Hooks.

Remember, the goal of Hooks is to make your code cleaner and easier to understand. If introducing Hooks doesn’t serve this goal, it might not be the right choice for your situation.

In the next section, we will discuss best practices for using React Hooks, helping you to get the most out of this powerful feature.

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Best Practices for React Hooks

Best PracticeDescription
Only Call Hooks at the Top LevelHooks should never be called inside loops, conditions, or nested functions. This rule ensures that Hooks are called in the same order each time a component renders, preserving the state and behavior consistency across multiple renders.
Only Call Hooks from React FunctionsHooks can only be called from the top level of your React functions. Don’t call Hooks from regular JavaScript functions. By following this rule, you ensure that all stateful logic in a component is clearly visible from its source code.
Custom Hooks Should Start with “use”When creating custom Hooks, start the name with “use”. This convention makes it clear that the function is a Hook. It also allows tools and libraries to automatically detect custom Hooks and apply optimizations.
Keep Hooks SimpleTry to keep your Hooks small and focused. This makes them easier to understand and reuse.
Use Custom Hooks to Extract Common LogicIf you find yourself writing the same logic in multiple components, consider extracting this logic into a custom Hook.
Test Your Custom HooksLike any other piece of code, your custom Hooks should be tested to ensure they work correctly.
Document Your Custom HooksJust like regular functions, custom Hooks should be documented to explain what they do, what arguments they accept, and what they return.

Final Thoughts

React Hooks, introduced in React 16.8, have revolutionized the way we write React applications. They allow us to use state and other React features without writing a class, leading to simpler and cleaner code. With a better understanding of the core Hooks (useState, useEffect, useContext, useReducer, useMemo), as well as how to create custom Hooks, you can now leverage the power of Hooks to write more efficient and maintainable code.

However, like any powerful tool, it’s crucial to understand when and how to use Hooks effectively. As we discussed, Hooks should only be used at the top level of your React functions and not inside loops, conditions, or nested functions. Furthermore, they should only be called from React functions. And when creating custom Hooks, always start the name with “use” to clearly indicate that it’s a Hook.

In addition to these rules, it’s recommended to keep Hooks simple, extract common logic into custom Hooks, and thoroughly test and document your custom Hooks. Following these best practices will ensure that your Hooks are effective, efficient, and easy to understand.

For your reference, you can also check out the below YouTube video to learn more about React Hooks:

Victor Yakubu

Victor Yakubu