What is React?

React is an independent and open-source front-end JavaScript library for building user interfaces.The current version of React 18 provides developers with improved features to create a Great User Experience. Some of the improvements are

• Automatic Batching: Groups all state updates which in turn improves performance.
• Transitions: Is now more sophisticated and differentiates between urgent and non-urgent user interactions.
• React Suspense: Allows for better Server-side rendering and improves the User Experience. as well as Performance

Let’s look at these in a bit more detail

1. Automatic Batching:
   

   Batching is one of the React features that combines all the updated states in a single update. Batched updates can be performed inside React event handlers, i.e., it only worked inside the synchronous React event handlers functions. These changes were made in React version 18 with automatic batching.In the example code below, it shows how the automatic batching helps to stop re-rendering the set Counter () function twice.

   

2. Transitions:
   

   Transition is an advanced concept introduced in React 18 that helps to differentiate between urgent and non-urgent updates.

   • Urgent Update: It reflects direct interaction like typing, clicking, pressing etc. This visual feedback is high priority for users.
   • Non-urgent Update: Non-urgent updates are not vital to the user like searching, which can be marked as no-urgent updates.

   For such use cases, startTransitions and useTransitions methods are used.

   • useTransitions: useTransitions is a hook concept that begins transitions, in addition to a value to track the pending state.
   • startTransitions: startTransitions is a method to initialize start transition where hooks can’t be used. Below is the example for startTransition where you can put your code which is non-vital to the end user.
     

3. Suspense:
   

   Suspense lets you declaratively specify the loading state for some of the component tree if it’s not prepared to be displayed. Suspense in React version 18 functions better when combined with transitions API. while you suspend the time of transition, React will halt already-visible content from being altered by a fallback. Rather, React will stop or delay the rendering until enough data has loaded to prevent an inferior loading state.
   Below is the example for Suspense that explains how to use a fallback property of it to show the loading state to the end-user.

   Concurrency

   Concurrency is the most important addition in React version 18. It is a confidential mechanism that makes it possible for React to prepare multiple versions of UI.

   For these, React uses a “dispatcher” internally which is responsible to compile and combine the callbacks.

   Before React 18, the user did not have any way to control the appeal order of these functions. Since the release of React version 18, React is providing some authority to this event loop to the user with a Transition API.

   How to upgrade to React version 18?

   You will need to install React 18 and DOM using npm/yarn.

   npm install react react-dom

   npm install react@latest react-dom@latest

   

   After upgrading to version 18, the following changes need to be made in the Index.js file:

   Note: – There is an error in the console while upgrading to version 18.
   
   To fix this console issue, the index.js is converted to the latest React version 18, which recommends a new root API. This new root API provides a user-friendly system for executing roots. The new root API also enables the new concurrent re-renders which fastens the coexisting features.
   
   Our React developers have experience of building complex applications using React technology. They use the latest Dev tools such as React-Redux, React Hooks, React Router, React Bootstrap etc. If you would like to develop a mobile or web application using React technology, then please feel free to contact us.

What is React? 

You may not judge a book by its cover, but a web application gets assessed by the visual aesthetics of the User Interface (UI) and its functionalities. React is a JavaScript library that provides front-end developers an incredible framework and hence is getting increasingly popular. Aside from the encapsulated and reusable components, the customization features enable developers to build complex UI with simple views. Creating secure, responsive, and interactive web applications is no longer a challenging task but an exciting innovation with the sophisticated React.js framework.  

If you foresee a career or aspire to become a sought-after web app developer, you want to get well-versant with ReactJS.  

Which are the must-have skills you need to stack up? (Pun intended!)

Top 9 Must-Have React Developer Skills in 2022 

1. Hypertext Markup Language (HTML)+ Cascading Style Sheets (CSS)

Honing any skill always starts with getting the basics right. If you are a front-end developer, get familiar with HTML and CSS languages before moving into ReactJS. The more thorough you are, the firmer the foundation for constructing a well-developed page, website, and eventually an application. Well-scripted codes deliver a cleaner user experience.

Ensure you know how to: 

• Write the code for semantic HTML tags and use them 
• Use CSS for Inline styling  
• Build responsive CSS layouts with the box-sizing properties 
• Use Flexbox for creating beautiful and reusable components
• Implement CSS reset to avoid cross-browser differences 
• Apply the three main design principles—fluid grid system, flexible images, and media queries
  

2. JSX (JavaScript XML) + Babel
   

Simply put, JSX is the syntax extension of JavaScript that allows you to write HTML in React. JSX expressions simplify writing component codes and rendering tree-like structures of React elements. Essentially, JSX helps developers create simpler and elegant pieces of code even when they are large blocks. Developers familiar with HTML and CSS will appreciate the ease of building React applications with JSX.  

However, to implement JSX, you require the transcompiler—Babel that converts the ECMAScript2015 (ES6) + source code into a backward-compatible version of JavaScript. The toolchain helps you use modern JavaScript language features. 

3. JavaScript Fundamentals + ECMAScript 6 (ES6)

React is fundamentally JavaScript, and that is why knowing the programming language features and having substantial experience working with it is necessary for a front-end developer. The 6th version of the ECMAScript that standardized the JavaScript has certain modern features to take note of: 

• Arrow Functions 
• Variables (let, const, var) 
• Array Methods  
• Destructuring 
• Modules
• Ternary Operator 
• Spread Operator 

The new features will enable you to write asynchronous code making the process more efficient. 

4. Hooks

Hooks is a super-cool feature that makes a coder’s life far easier. Ask any experienced React developer, and they would tell you what a nightmare it was to refactor class components and render props with verbose code before Hooks got released in 2018. Hooks simplified the methods of updating the state and implementing the lifecycles of function components.  

Working with Hooks will help you improve the user interface with enhanced code readability, reusability, and testability.  

5. Virtual Document Object Model (VDOM) and Event Handling Facility

The biggest drawback of the actual DOM was that any manipulation of a single element in the tree structure would trigger the framework to rebuild every object. The more updates to the DOM, the slower the operations got, making it very cumbersome for developers. That problem got resolved only after the innovation of the Virtual DOM (VDOM). The React VDOM virtually handles all the changes made to the objects but updates only the necessary changes to those particular objects in the actual DOM when everything is finalized, thus saving you precious time.  

6. NodeJS + Node Package Manager (NPM)

Using NodeJS is NOT a prerequisite for ReactJS web app development but can definitely accelerate projects if utilized in combination. While ReactJS takes care of the front-end aesthetics of the web application, Node is a JavaScript language that is ideal for backend development. NodeJS helps maintain continuous streaming and server load balance for real-time data-intensive web applications. The full-stack JS framework improves scalability and speeds up code execution.  

Use the NPM cloud registry for managing all NodeJS package repositories or dependencies and the JavaScript libraries.  

7. Redux

One of the most important aspects of web applications is that they are expected to behave consistently across client, server, and native environments and must be easy to test, too.  You need Redux, the state management library for ReactJS to centralize and manage the global state of the application or to maintain specific patterns while updating the state.  

8. Technical Application Skills

Aside from having a command of the JavaScript language and system architecture, you must have knowledge and expertise of certain other tools crucial for writing clean code for the front-end development of ReactJS applications.  

• Build tools for component visualization 
• Modular bundle analyzer  
• Development automation tools 
• Tools for reporting crashes and managing testers, or beta version distribution tool. 
• Testing utilities or code evaluation tool to confirm if it complies with the JS 
• Form building API or libraries 
• Debugging extensions

9. Soft Skills

Even as you check every box for technical skills, your soft skills are equally important. You might want to cultivate these soft skills that employers or clients will value in a front-end developer: – 

• Creativity 
• Emotional intelligence 
• Clarity in communication  
• Learning/ Growth mindset 
• A keen eye for detail/observation  
• Critical/Analytical thinking 
• Time management, especially with deadlines 
• People management/ interpersonal skills 
• Accountability 
• Problem-solving attitude 
• Team player’s spirit 

 What Is the Future for React Developers? 

The post-Covid world has grown more digital than ever before. We rely on web/mobile applications for everything from buying groceries to improving physical and mental health. The growing majority of organizations are now showing a preference for ReactJS while creating a digital platform for their business since it provides a speedy, scalable, easy-to-maintain, and extremely SEO-friendly environment. Consequently, there is a noticeable upsurge in the demand for developers with a robust ReactJs skillset. And there’s no trough to this wave anytime soon!  

 Build on the 9 ReactJS skills, related technical skills, and 11 soft skills shared here. 

Create engaging web applications.  

And find yourself in the league of the most sought-after ReactJS developers of 2022.   

MetaSys React team makes the best use of all the new exciting features of React like React Hooks, React Bootstrap, React Redux and React Router to build complex web and mobile applications. So if you have any such requirement, then please feel free to contact our React Programmers.  

React Hooks are functions that allow you to hook into React lifecycle and state features. They primarily serve as an alternative for classes. They can help in keeping your components clean and perform better. Hooks are a recent  addition in React version 16.8.0.

In this article, we are going to show you how to convert a React class into a functional component using the useState Hook.

Hooks don’t work inside classes because they let you use React without classes. We will use the built-in hooks instead of React lifecycle methods. Eg. useState, useEffect, useRef etc.

We are covering useState, useEffect, useRef React hooks in this article. useState() is used to replace the constructor functions and state declarations. While useEffect() is used to replace componentDidMount() and componentDidUpdate(). You can use useEffect as many times as you need to in single component. And the last one, useRef has another cool usage besides DOM refs, it is also a generic container whose current property is mutable, it also can hold any value similar to an instance property of a class.

Steps to convert a React class component into a functional component using React Hooks –

Step 1. Change ‘class ComponentName extends Component’ With ‘function ComponentName(props)‘

Step 2. Remove “this.” And “this.state” from the entire component.

Step 3. import React, { useState } from ‘react’

Step 4. Remove the constructor. Add its logic as shown above in the image for initializing the state variables with the help of useState hook.

Let’s understand conversion into useState, useEffect and useRef with examples –

• useState() Hook –

The parameter of the useState hook is the initial value of the state. This hook provides the array with two values – the first is the name of the state and the second is the function name which updates the value of that state.

Eg.

const [num, setNum] = useState(0); //declaration

setNum(10) //use

Here num is the state name, setCount is the function that you can use anywhere in the component to update that state.

Here are some examples of setting or initializing state variables for different data types –

//Set an Integer

const [num, setNum] = useState(0);

setNum(10);

//Set a String

const [name, setUsername] = useState(‘John’);

setUsername(‘Smith’);

//Set a Boolean

const [isValid, setIsValid] = useState(false);

setIsValid(true);

//Set and Array

const [items, setItems] = useState([]);

setItems([0,1,2,3,4]);

setItems([{id:0, color:”red”},{id:1, color:”green”},{id:2, color:”blue”}]);

//Set and Object

const [form, setValues] = useState({

id: 0,

firstName: ‘’,

lastName: ‘’,

subscribe: false

})

setValues({

…form,

firstName: ‘Jamie’,

subscribe: true

})

• Replace lifecycle methods (compentDidMount, componentWillUnmount,

 componentWillReceiveProps, componentDidUpdate) with useEffect

e.g.

const [items, setItems] = useState([]);

const [num, setNum] = useState(0);

1. compentDidMount

useEffect(()=>{

setItems(items);

}, [])   // Here empty array indicates don’t look for any updates

b.componentWillUnmount

useEffect(()=>{

return () => {console.log(‘unmounting the component’)}

},[])

c. componentDidUpdate/componentWillReceiveProps

This will get executed when your ‘num’ state variable and ‘id’ props will get updated.

useEffect(()=>{

if (!isEmpty(num))

{

console.log(‘num changed = ’,num);

setItems(items);

}

if(!isEmpty(props.id))

{

console.log(‘props.id changed = ’,props.id);

}

},[num, props.id])

• Use of useRef

const [num, setNum] = useState(0);

const prevNumRef = useRef();

useEffect(()=>{

prevNumRef.current = num;

})

const prevNum = prevNumRef.current;

return <h1>Current value : {num}, previous value = {prevNum}</h1>

Advantages

1.With React hooks, the component will be cleaner and easier to read (fewer lines of code). Hooks are easier to work with and to test.

2.It is easy to make code reusable. They don’t create another element in DOM like HOCs in React do.

3. useState – it allows to update different states with specific functions. The ability to move the state update logic as a separate hook.

Disadvantages

1.useEffect hook allows to merge three lifecycle methods such as componentDidMount, componentWillUnmount and componentDidUpdate into one and the issue with useEffect is the second parameters ,i.e. the array that we need to pass to define this behaviour. It is not explicit enough.

2.React Hooks are new additions to React. So to convert and test a complex class can be a time-consuming task initially .

3.Since it is relatively a new addition it may not be compatible with all third party libraries. But this is rapidly changing .

This is all about React Hooks in a nutshell. If you are looking to build any a mobile or web application using React technology, then please contact us.

Happy coding!