Functional Components vs. Class Components in React.js - Learn ReactJS (2023)

The history of React.js componentsFunctional components in ReactClass components in React.jsThe difference between functional and class componentsBonus: Building an App with Flatlogic Platform

When you start to code with React you may get confused by some things in React, like JSX syntax or the difference between functional and class components. JSX is an interesting syntax extension to JavaScript that was developed to make the process of writing the UI elements more comfortable. The development with React doesn’t require using JSX, just like our article is not about it either. We are going to discuss Functional vs Class components. Let’s start.

The history of React.js components

We should jump into the history of React first to understand how React components evolved. React, created by Facebook software engineer Jordan Walke, is an open-source front-end JS library for building interactive user interfaces. The first release was in 2013, with 0.3.0 version. React has got further development and updated several times every year. The React team added more and more new features to the library to give developers more tools for coding. Among the most famous and loved features are the virtual DOM, one-way data-binding, JSX, reusable components, declarative programming, stable code, fast rendering of UI elements, great performance optimization opportunities. The current version at the time of writing this article is 17.0.1.

Along with all these benefits React offered it also gave developers two types of components they could use to create UI components. It can be supposed that both types of components provide the same opportunities for writing UI elements, and the choice depends only on the developer’s preferences. Well, it wasn’t true. The real situation was that class components were the only viable option to develop complex apps with React. The reason was that using class components you get a large number of capabilities, for example, state, while functional components didn’t provide such an option. However, the situation changed when React v.16.8 was released in 2019. A new version contained an update that was meant to take the development with functional components to the next level. React offered Hooks for functional components. The introduction of Hooks made it possible to write the entire complex application using only functions as React components. This is a deeply significant event that changed the way of React apps development. Keeping that in mind, we are going back to the present time and find out what is happening now and what functional and class components are.

Functional components in React

Functional components in React are just JavaScript functions like this:

function Foo(props) {
return <h1>Who is living young, wild, and free? – {}</h1>;
const element = <Foo name=”Me!” />;
ReactDOM.render(element, document.getElementById(‘home’));

In our case, we render an element that represents the user-defined component calledFoo. The element passes JSX attributename=” Me”as a prop to our function componentFoo, which returns a<h1>Who is living young, wild, and free? – Me!</h1>element as the result.

Props are inputs for both types of components. One of the main tasks of props is to pass information from component to component. It’s especially necessary if you want to build a dynamic user interface. However, there is one important rule that you shouldn’t forget: props are read-only. That means that all React components shouldn’t change their inputs and the same props must return the same result. Components that respect their props are called “pure”. That rule works both for class and function components.

JSX is a special extension that allows us to place HTML elements right inside JavaScript code without using additional methods like createElement(). All your HTML tags will be converted into React elements after compilation. JSX may be convenient, however, it is an optional instrument for development. To see how the same blocks of code look like with/without using JSX try the online Babel compiler.

Another way of writing function components is by using an arrow function.

An example of an arrow function:

const App = () => { //that is an arrow function
const greeting = ‘Hello Function Component!’;

return <Headline value={greeting} />;

const Headline = ({ value }) =>

export default App;

Arrow functions have some benefits:

The code written with arrow functions looks compact. Functions are easier to write and read. One of the reasons is an implicit returnby simply omitting the curly braces(see videowith an example).Arrow syntax doesn’t contain its context and automatically bind this to the surrounding code’s context

But since arrow functions give one more way to write code (along with standard functions and classes) you need to set rules when we use any of them. As an example you can stick to the following rules:

If you work with global scope and Object.prototype properties use function.If you work with object constructors use class.If you face any other situation use arrow function.

The examples above are calledstateless function componentsbecause they just take props as an argument and return a react element. They don’t manage state and don’t have a lifecycle, while class components do. However, you can use Hooks with them that allow you to work with state and lifecycle and add even more features. We will speak about that in the comparison below.

Class components in React.js

Let’s start with an example:

class Foo extends React.Component {
render() {
return <h1>Who is living young, wild, and free? – {}</h1>;

It is a regular ES6 class that extends the component class from the react library. To return HTML you have to userender() method in it.

Class components work fine with props as well as functional components do. To pass the props to a component you can use a syntax similar to HTML attributes. In our sample case we need to replace with in therender()body to use props.

Additional benefits class components offer by default are state and lifecycle. That is why class components are also known as “stateful” components.

(Video) Class Components vs Functional Components in React (Which is better? - Beginner's Guide)

The state of a component is an observable object that holds some information and controls the behavior of the component. The difference between props and state is that props don’t change over time during the lifetime of a component. The state holds the data that can be changed over time and changes the component rendering as a result.

The state of a component is supposed to have the initial this.state that can be assigned with a class constructor. The class constructor is a special JavaScript method that allows to bind event handlers to the component or to initialize the local state of the component.

If you don’t need to handle any of both cases above the implementation of a constructor is unnecessary. Example of a constructor:

constructor(props) {
this.state = {};

Constructor()function inside a React component requiressuper(props)before any other statement.Super(props)is a reference to parentsconstructor() function,that React.Component base class has. When we define a newconstructor()inside a class component, we replace the baseconstructor()function. However, it has some code inside of it we still need. So to get access to that code we callsuper(props)– that is why we have to addsuper(props)every time we define aconstructor()inside a class component. Theconstructor()is called before the React component is mounted.To use state in a class component we must define the initial state of it in the constructor. Instead of callingsetState(), we need to assign the initial state withthis.statecommand in the constructor. It’s the only case when we are allowed to change the state directly by assigning its value, otherwise usesetState()instead.Constructor()has other rules you should be aware of, you can read about them on the link.

Differentiating Functional vs Class components

1.State and lifecycle

Well, the standard answer to the question about the difference between functional and class components was that class components provide developers with such features as setState() and lifecycle methods componentDidMount(), componentWillUnmoun(), etc., while functional components don’t. That was true because functional components are plain JavaScript functions that accept props and return React elements, while class components are JavaScript classes that extend React.Component which has a render method. Both state and lifecycle methods come from React.Component, so they were available only for class components. The widespread advice was something like that: “Go with functional if your component doesn’t do much more than take in some props and render”. You had no options on how to build complex UI and class components dominated in React development for a while.

However, that has changed with the introduction of Hooks. To replace setState method to work with the state in class components React offers useState Hook.

To work with components lifecycle classes have such methods like componentDidMount, componentWillUnmount, componentWillUpdate, componentDidUpdate, shouldComponentUpdate. Functional components have got a tool to work with the same methods using only one Hook useEffect. You can think of useEffect Hook as componentDidMount, componentDidUpdate, and componentWillUnmount combined.

Standard class methods work well but do look not very elegant. Functional components offer an elegant and simple decision: instead of using multiple lifecycle methods, we can replace them with one Hook useEffect. What React developers write about Hooks:

“Our goal is for Hooks to cover all use cases for classes as soon as possible. There are no Hook equivalents to the uncommon getSnapshotBeforeUpdate, getDerivedStateFromError and componentDidCatch lifecycles yet, but we plan to add them soon. It is an early time for Hooks, and some third-party libraries might not be compatible with Hooks at the moment.”

an official React documentation

So Hooks are more addition to functional components rather than a replacement of class components.

2. Syntax

The obvious difference is the syntax. Let’s examine several examples.

How we declare components.

Functional components are JavaScript functions:

function FunctionalComponent() {
return <h1>Hello, world</h1>;

Class components are classes that extend React.Component:

class ClassComponent extends React.Component {
render() {
return <h1>Hello, world</h1>;

To return our h1 we need the render() method inside a class component.

The way we pass props.

Let’s say we have props with the name “First”.

<Component name = “First” />

Working with functional components, we pass the props as an argument of our function using the construction “”.

function FunctionalComponent(props) {
return <h1>Hello, {}</h1>;

With class components, we need to add this. to refer to props.

class ClassComponent extends React.Component {
render() {
return <h1>Hello, {}</h1>;

Handling state.

To handle state functional components in React offer useState()Hook. We assign the initial state of count equal to 0 and set the method setCount() that increases it by one every time we click a button. The component returns the number of times we clicked the button and the button itself. The initial state is used only during the first render. The type of argument can be a number, string, object, or null. To learn more about that useState() Hook see the official documentation.

(Video) React JS Functional Vs Class Components | React JS Tutorial #6

const FunctionalComponent = () => {
const [count, setCount] = React.useState(0);
return (
<p>count: {count}</p>
<button onClick={() => setCount(count + 1)}>Click</button>

Class components work a bit differently. They use setState() function, require a constructor, and this keyword.

class ClassComponent extends React.Component {
constructor(props) {
this.state = {
count: 0

render() {
return (
<p>count: {this.state.count} times</p>
<button onClick={() => this.setState({ count: this.state.count + 1 })}>

The underlying logic is similar to the logic in functional components. In constructor() we declare a state object, state key “count” and the initial value equal to 0. In render() method we use setState() function to update the value of our count using this.state.count and the app renders the number of times the button was clicked and displays the button itself. The result is the same, but the same functionality requires more lines of code for class components. However, it doesn’t mean that the code written with class components will be more cumbersome than the code made with functional components, but the code definitely will be bigger.

Lifecycle methods.

With version 16.8 React allows working with lifecycle methods of components. That means that developers have better control over functional components and can manipulate their life phases (initialization or setting the initial state, mount, update, unmount). The initialization is explained in the paragraph above, let’s look at the next stage.


The useEffect Hook for functional components:

const FunctionalComponent = () => {
React.useEffect(() => {
}, []);
return <h1>Hello, World</h1>;

The componentDidMount method for class components:

class ClassComponent extends React.Component {
componentDidMount() {

render() {
return <h1>Hello, World</h1>;

The useEffect Hook possesses two parameters: the first is the “effect” itself that is going to be called once after every render of the component. The second parameter is an array of observable state or states (or so-called a dependency list). useEffect Hook only runs if one of these states changes. Leaving the second parameter empty useEffect Hooks runs once after render.


The useEffect Hook for functional components:

function BooksList () {
const [books, updateBooks] = React.useState([]);
const [counter, updateCounter] = React.useState(0);

React.useEffect(function effectFunction() {
if (books) {
updateBooks([…books, { name: ‘A new Book’, id: ‘…’}]);
}, [counter]);

const incrementCounter = () => {
updateCounter(counter + 1);


The componentDidUpdate method for class components:

componentDidUpdate(prevProps) {
// Typical usage (don’t forget to compare props):
if (this.props.userID !== prevProps.userID) {

As we have mentioned the second parameter in the useEffect hook is an array of observable states, once a counter changes it triggers the effectFunction hook.


The useEffect Hook for functional components (yes, again):

const FunctionalComponent = () => {
React.useEffect(() => {
return () => {
}, []);
return <h1>Bye, World</h1>;

The componentDidUnmount method for class components:

class ClassComponent extends React.Component {
componentDidMount() {

render() {
return <h1>Hello, World</h1>;

3. Hoisting works only for functional components

Hoisting is a concept that appeared in ECMAScript® 2015 Language Specification. According to that concept, JavaScript moves variable and function declarations to the top that allows you to access a variable or a function first and only then declare it. Actually, JS doesn’t move the code, it puts declarations in memory during the compile phase that allows calling a function before you declare it. That is not true to classes, trying to get access to a class before the declaration throws a ReferenceError exception.

(Video) React Functional Components VS Class Components Practical Differences : Part 14

An example of the code where we call function before its declaration:

function catName(name) {
console.log(“My cat’s name is ” + name);
// The result of the code above is: “My cat’s name is Tiger”

Even though we call the function before we write it, the code works great. The following code with class declaration will throw an error:

const p = new MyName(); // ReferenceError
class MyName {}

That is not all. JavaScript only hoists declarations, not initialization. If we declare a variable and call it before the initialization it returns undefined. See example:

console.log(myName); // Returns undefined, as only declaration was hoisted
var myName; // Declaration
myName = “John”; // Initialization

Initializations with keywords let and const are also hoisted, but not initialized. That means that your app is aware of the variable existence. However, it can’t use it until variable initialization. The example below will throw a ReferenceError:

myName = “John”;
let myName;

That example will not run at all:

myName = “John”;
const myName;

Why does it matter? Let’s get back to React and create a simple React app in index.js file with one component in a separate file Component.js:

import React from ‘react’;
import {render} from ‘react-dom’;
import App from ‘.Component’;render(

And the component itself:

const Component = () => {
return (
<div>Hello, React</div>
export default Component;

The app renders a text: “Hello, React”. Since the component is small, there is a sense not to separate it and merge it into index.js file like this:

import React from ‘react’;
import {render} from ‘react-dom’;
const Component = () => {
return (
<div>Hello, React</div>

And we get an undefined error because we try to render a component that was declared with an arrow function before we initialize it.To repair the code just re-order the declaration and put it before calling render().

4. The way they capture values (props)

One interesting experiment (the original article with full analysis can be found here) that took place on the Internet is the following React app.

It’s a simple app that simulates a social network request to follow someone. The app displays a drop-down list with three profiles to follow, static greetings text, and two buttons that call the confirmation alert to start following a chosen person. The confirmation alert appears 3 seconds later after you clicked the button. The delay is set with setTimeout() method.

The list of the experiment is the following:

Choose a profile to followClick a follow button with “function” text in brackets near itChange a profile to follow in the drop-down list before the confirmation alert appearsCheck the name in the confirmation alertRepeat the same four steps above for the follow button with “class” text in brackets

In the first case with the functional button switching the name doesn’t affect the confirmation alert. With the class button switching the name changes the alert message, even though you clicked to follow Dan but switched to Sophie, the alert message will be “Followed Sophie”. The correct behavior is the first, of course. No one likes to follow a wrong profile on social media.

The reason for such a behavior lies in the essence of functional and class components. Let’s examine these lines of code:

class ProfilePage extends React.Component {
showMessage = () => {
alert(‘Followed ‘ + this.props.user); };

function ProfilePage(props) {
const showMessage = () => {
alert(‘Followed ‘ + props.user);

(Video) Function and Class Component in ReactJs - 11 - ReactJs in telugu

As we have said props are read-only, they are immutable. So once you pass the props to a functional component ProfilePage(props), the only remaining task for React is to render it after the time is up.

On the other hand, this is mutable. And it’s okay because it allows us to use states and lifecycle methods correctly. So if we pass other props while the alert message doesn’t appear, changes and showMessage method displays the last version of props. Our showMessage method is not tied to any particular render and that may become a problem.

There are several potential solutions that actually work. One of them is to catch props at the time of render like this:

class ProfilePage extends React.Component {
render() {
// Capture the props!
const props = this.props;
// Note: we are *inside render*.
// These aren’t class methods.
const showMessage = () => {
alert(‘Followed ‘ + props.user); };

const handleClick = () => {
setTimeout(showMessage, 3000);

return <button onClick={handleClick}>Follow</button>;

So we stuck our certain props to a particular render().

5. Running tests

There are two most popular instruments for running tests: Enzyme and Jest. Enzyme is a JavaScript testing utility for React that allows testing React components’ display. Jest is a JavaScript testing framework for writing tests, in other words, for creating, running, and structuring tests.

These two instruments do a great job on both types of components. There are some specificities in running tests for functional components, like the fact, that state hooks are internal to the component and can’t be tested by calling them. However, instruments and methods are similar.

6. Performance difference

There is an opinion that functional components show a greater performance compared to class components. The point is that the React functional element is a simple object with 2 properties: type(string) and props(object). To render such a component React needs to call the function and pass props – that is all.

Class components are more complex: they are instances of React.Component with the constructor in it and complicated system of methods for manipulating state and lifecycle.

Theoretically, calling a function should take less time than creating an instance of a class. Well, one developer held a test: he rendered 10000 elements of stateless components and class components. You can see the result here. As we see from the 3 experiments there is no difference in render time between rendering class and functional components.

To sum up everything above:

Сlass components were the only option to add states to components and manipulate lifecycle. However, it has changed since the introduction of Hooks, which gave the same opportunities to functional components as classes had.The major difference is the syntax. It relates to the way we declare components, pass props, handling states, manage lifecycle.Function components capture the props and state by default. It is not a bug, but a feature of functional components.Functional components require less code to write an equal component. However, that doesn’t mean that functional components more readable and convenient to use. If a developer is used to work with object-oriented programming, he finds using class components much more comfortable. Those who are used to functional programming like functional components more than class components.There are two most popular tools to test functional and class components: Enzyme and Jest. They work great for both types of components.There is no big difference in render time between class and functional components.

Today you can build a whole app using only functional components. It was impossible till 2019. That became possible thanks to Hooks. Does Hooks replace class components in the coming years? We don’t think so, because there are still some features that functional components can’t reproduce. And there will always be developers, who are used to working with objects rather than with functions. However, we await the growth in functional component popularity and an increase in the number of features for Hooks. And it’s likely that the functionality Hooks will provide goes beyond class components possibilities.

Bonus: Building an App with Flatlogic Platform

Understanding Functional and Class components is an important stepping stone in React development. Crafting Apps by hand requires a thorough understanding of all the intricacies of the library. However, there’s a quicker way for those who aren’t technically adept or lack time to write the whole thing from the ground up. Some people need a unique App with functions not seen elsewhere, but most apps are different combinations of the same parts and features. We used that insight when developing theFlatlogic Platform.

Flatlogic Platform is a constructor-style tool for combining pre-built parts into brand-new applications. It requires a few steps from you. Keep reading to know what those are!

#1: Name the Project

This step is what it sounds like. The only valuable advice we can think of is to pick a name that is easy enough to associate with the project.

#2: Choose stack

Next up, choose the technologies your App’s parts will run on. Those are underlying technologies for back-end, front-end, and database. In this example, we’re picking a combination of React, Node.js, and MySQL. But all other combinations are perfectly compatible, too.

#3: Choose Design

You’ll have several design schemes to choose from. Some are transparent and light, others with a heavier feel. Pick the one you like, this part is purely aesthetical.

#4: Create the schema

The schema is the structure of a database. Names of fields, types of data, the way the App processes said data… Every aspect that defines how the database works is a part of the schema. It might be tricky at first, but you’ll get the hang of it. A thorough review of what your App is supposed to do will be helpful. If you’re short on time or unsure, pick one of the pre-built schemas. One of them is bound to suit your needs.

#5: Review and generate

The heavy decision-making is over. It’s time to check if every choice you’ve made is the way you want it to be and (assuming everything’s fine) hit “Finish”.

The compilation takes a couple of minutes on most devices. Upon completion, the Platform will offer you your very own App. Hit “Deploy”, host it locally in one click or push it to GitHub for further use or adjustment.

Flatlogic Platform helps create simple yet functional and smooth Apps for commercial and administrative purposes, make sure you give it a try! Happy developing and see you in the next articles!

You might also like these articles:

React.js vs. React Native. What are the Key Differences and Advantages?Top 12 Bug Tracking ToolsAngular vs. Bootstrap – 6+ Key Differences, Pros, and Cons

The post Functional Components vs. Class Components in React.js appeared first on Flatlogic Blog.

(Video) 99% React Developers Fail to Answer THIS Question!


Should I learn class components or functional components in React? ›

If you love functional programming and don't like classes, go functional. If you want consistency between all components in your codebase, go with classes. If you're tired of refactoring from functional to class based components when you need something like state , go with classes.

Are functional components better than class components React? ›

It shows a greater performance than class components. The point used to measure this is made of a simple object with the type(string) and props(object) 2 properties. Rendering such a component needs to call the function and passing props.

Should I learn class components React in 2023? ›

If you are wondering whether you need to learn class components in 2023, you do not. As you begin to learn React, you will hear about this thing called a class component which is based around a normal JavaScript class. This is no longer necessary to learn as a React developer, but it can still benefit you to learn it.

Do I need to learn class-based components in React? ›

Function components were considered "state-less". With the addition of Hooks, Function components are now almost equivalent to Class components. The differences are so minor that you will probably never need to use a Class component in React.

Is class component outdated in React? ›

There is no plans to remove class components. Library developers recommend use functional components in new code. You can write functional or class components if you can keep code clean and easy to understand for any develop.

Do people use class components in React? ›

Class components are basically JavaScript Object Oriented classes with functions you can use to render React components. The advantage of using classes in React is that they contain lifecycle methods that identify when state changes and updates the global state or the component state using the keyword this.

What are the disadvantages of functional components in React? ›

Functional components don't support state, refs, or lifecycle methods. They can't extend PureComponent either. Sometimes, you'll create a functional component only to realize that you need one of these class-only features later. In these situations, it's a hassle to manually convert to a function into a class.

Why should I use functional components over class components? ›

Unlike class components, functional components are stateless, which means that there are no lifecycle methods or state management. However, with React Hooks, there are provided functions for us to do so, such as useState() & useEffect() . To learn more about hooks, please check out the documentation.

Why prefer functional components over class components? ›

Functional component are much easier to read and test because they are plain JavaScript functions without state or lifecycle-hooks. You end up with less code. They help you to use best practices.

How much time is required to become proficient in ReactJS? ›

It will take you between one and six months to become proficient with the fundamentals of React. How quickly you learn React depends on your prior software development experience and how much time you are willing to put into learning.

Are functional components the future of React? ›

The Future of Class Components

There are a great number of legacy projects which still use class components but React's team recommends using functional components for all newer projects. All the modern React tutorials also focus only on functional components.

Is ReactJS still relevant in 2023? ›

The ease and optimum results offered by the ReactJS framework have made it the top-in-demand skill of the year 2023.

Is it worth learning React classes? ›

Learn React With Treehouse

As you can see, learning React is a great choice for aspiring front-end web developers. It allows development teams to build web apps faster and maintain them more easily as they grow over time. It's also a common prerequisite for many front-end web development jobs.

What is required to learn ReactJS? ›

The essential prerequisites for ReactJS are HTML and CSS, Fundamentals of JavaScript and ES6, Git and CLI (Command Line Interface), and Package Manager (Node + Npm).

Should you always use functional components in React? ›

Yes functional components are better in React, with the introduction to the React hooks, we can do so much of things in functional components, even we can use lifecycle methods inside the functional component. We can even create functional components using ES6 arrow functions.

Should I use class component or functional component? ›

In class components, the render method will be called, whenever the state of the components changes. On the other hand, the Functional components render the UI based on the props. Class Components should be preferred whenever we have the requirement with the state of the component.

Are class components dead? ›

Class components are not dead.

Why not use class components? ›

The downsides of using classComponents is that they come with a bunch of preloaded stuff inside them whether you want it or not. If you are just using state in a Component for example, you are still loading all of the other stuff that comes along with it each time you render that component.

Are functional components better? ›

The biggest advantage of the functional component is that they have your code easily and also make your program easy to read and understand for others.

Are React Hooks better than classes? ›

The origin of React hooks

Hooks make React so much better because you have simpler code that implements similar functionalities faster and more effectively. You can also implement React state and lifecycle methods without writing classes. Below are code examples to illustrate React class and functional components.

What are the 3 types of components in React? ›

Types of React Components Discussed
  • Functional Components.
  • Class Components.
  • Pure Components.
  • Higher-Order Components.

Should I use React lazy to all components? ›

This is because the component will only be loaded when it is needed, and it will only be loaded once. So you should only use React. lazy when you need to load a component asynchronously. The component is not readily needed in the initial render of the app, and it is not needed in the render of a specific page.

Can we use React hooks in functional component? ›

There are 3 rules for hooks: Hooks can only be called inside React function components. Hooks can only be called at the top level of a component. Hooks cannot be conditional.

Which is faster class component or functional component? ›

There is an opinion that functional components show a greater performance compared to class components. The point is that the React functional element is a simple object with 2 properties: type(string) and props(object). To render such a component React needs to call the function and pass props – that is all.

Do we really need class components anymore? ›

React class components are rearly used in modern React development but we still need to know them in case we need to work on old legacy projects. If you want to embrace modern React, then you should use function components with hooks. Most tutorials today are teaching React development with no class components at all.

Why should I use classes instead of functions? ›

By using classes, you're ensuring that methods are only used on one set of data. This adds to the security of the code because you're less likely to use functions where they don't belong.

Can we mix class and functional components? ›

Its perfectly alright to have a mix of both functional and class components.

Can I learn React in 7 days? ›

A beginner programmer should be good enough with React in a about a week. This is not counting the tools and other libraries that complete React like for example, Redux or Relay. There is an important question about the order with which you need to learn things. This order would vary based on what skills you have.

Can I learn ReactJS in 2 weeks? ›

ReactJS Basics

If you are a beginner or already have some programming experience, it will take you one to four weeks to completely master the basics.

Can I learn ReactJS in 10 days? ›

As with any skill, the more you practice, the better you get. React has a good learning curve in comparison to other web development frameworks, and so you should have no trouble learning the basics in a few days or weeks, and mastering the language in a few months.

What are the 3 lifecycle states in a React functional component? ›

A React component undergoes three different phases in its lifecycle, including mounting, updating, and unmounting. Each phase has specific methods responsible for a particular stage in a component's lifecycle.

Why did React move to functional components? ›

They promote more precise code. Easier to think about and write. They simplify how you interact with state and the life-cycle of components. They reduce the amount of code to read and write.

What is the average salary of a React developer? ›

The national average salary for a ReactJS Developer is ₹4,87,355 in India.

What is replacing ReactJS? ›

The Bottom Line: Will Next.js Replace React.

Why Nextjs is better than ReactJS? ›

js requires less code, whereas React framework requires a long line of coding. React can be the right choice if you wish to build a large complex web application with complex routing and heavily data-driven components. Next. js can be a good choice for you if you wish to build a static website or JAMstack application.

Why is React so difficult? ›

However, React is also difficult because it deals with advanced concepts like functional programming, compartmentalizing and passing state, using it with backend frameworks, and using it in conjunction with 3rd party software. If you want to learn React, the most important thing is to get started today and don't quit.

How difficult is to learn ReactJS? ›

Thankfully, React is easy to learn, but only once you have foundational knowledge in JavaScript. Of course, the difficulty that comes with learning anything new is somewhat subjective. Regardless of your prior experience, plenty of resources are available to help make React easier to learn.

Can I learn React quickly? ›

For a programmer who is already familiar with HTML and at least one other programming language, learning React will take no more than a single day. React may be learned by a novice programmer in a matter of days. There are more libraries and technologies that may be used with React, such as Redux or Relay.

Should I master JavaScript before learning React? ›

You don't need to be a JavaScript expert to start your ReactJS journey, but just as knowledge of ingredients is a must for any chef hoping to master cooking, the same is true for learning ReactJS. It's a modern JavaScript UI library, so you need to know some JavaScript.

Do I need to be an expert of JS to learn React? ›

React is a JavaScript-based Library for seamlessly building interactive front-end for websites and apps. Since React is based on Javascript, we recommend that you first learn JavaScript to a certain level.

How do I become an expert in ReactJS? ›

At a high level, React developers should be able to:
  1. Work with and write semantic HTML tags.
  2. Work with and write CSS selectors.
  3. Implement a CSS reset.
  4. Understand the box model and how to reset to border-box.
  5. Understand flexbox.
  6. Work with and implement responsive web principles including the proper user of media queries.
Nov 2, 2022

Is it worth testing React components? ›

Unit testing is an essential part of the development process for React applications. By writing unit tests for your React components, you can ensure that your components are working as expected and catch bugs early in the development process.

Do you need to know functional programming for React? ›

React doesn't encourage inheritance it supports composition. It's very important to know functional programming if you are just getting started with the react.

Should I learn React or web components? ›

However, there's a difference. A React component can only be reused in the React application. On the other hand, a web component can be used in any HTML document or any frontend library. Web components can be used in React, Angular, Vue, etc., as it is included in the HTML specification and is native.

When to use class components and functional components React? ›

In class components, the render method will be called, whenever the state of the components changes. On the other hand, the Functional components render the UI based on the props. Class Components should be preferred whenever we have the requirement with the state of the component.

Why React functional components are better? ›

The biggest advantage of the functional component is that they have your code easily and also make your program easy to read and understand for others.

Which is better React Hooks or class components? ›

The major difference between Hooks and class-based state is that hooks are used inside of the functional component. One thing to keep in mind is that never call hooks inside of a any logic, it should always be on the top level! useState() is a hook that allows you to play with state in functional components in react.

What are the cons of functional component? ›

Cons of Functional Components:

People who are used to object-oriented programming format, find using Class components much easier to pick up. The syntax is a little difficult to understand for those who are used to the Class model.

Which is better class or functional component? ›

Nothing is better, because both have pros and cons. But class components are important to understand React flow and lifecycle methods. The new learner should practice React using class components. Once they are familiar with class components, they can learn and use functional components.

Can you mix class and functional components React? ›

You can't use Hooks inside a class component, but you can definitely mix classes and function components with Hooks in a single tree. Whether a component is a class or a function that uses Hooks is an implementation detail of that component.

What are the disadvantages of class component in React? ›

Also, class components have downsides;
  • Confusing (both human and machines, especially at binding and this keyword)
  • Lifecycle methods, logic spread over different lifecycle methods.
  • Hard to test compared to functional components.
  • Compiled code size and compile time.
Oct 29, 2018

What is most important in React? ›

The key feature of React is composition of components. Components written by different people should work well together. It is important to us that you can add functionality to a component without causing rippling changes throughout the codebase.

Should I learn React with classes or Hooks? ›

The origin of React hooks

Hooks make React so much better because you have simpler code that implements similar functionalities faster and more effectively. You can also implement React state and lifecycle methods without writing classes. Below are code examples to illustrate React class and functional components.

Should I learn all React Hooks? ›

What five React Hooks do you need to know most of all? There are more hooks than these 5, but the others are not needed as often. So yes, you should learn the latest React features. Jump into using hooks right away.

Why use Hooks instead of class? ›

Hooks allow you to use local state and other React features without writing a class. Hooks are special functions that let you “hook onto” React state and lifecycle features inside function components.


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