Published in: ReactJS

What is JavaScript for React? And How to Get Started With it

Author Niraj Gohel

Published on: October 5, 2023

Introduction

About JavaScript for React

JavaScript – do you know it? React, a leading web development framework, is deeply intertwined with JavaScript for creating interactive web applications. In the realm of web application creation, knowledge of JavaScript becomes crucial especially when you’re considering React. Why? It’s because maintaining organized codes and efficiently using JavaScript modules is essential for the smooth functioning of React web applications. Interestingly, react reusable components and virtualDOM make it even superior to plain JavaScript for ecommerce-based websites. So, if you’re thinking about React, think JavaScript first.

Why Should You Learn it?

Have you not heard? JavaScript is the lifeline of React! Learning JavaScript basics lights the path to React. Makes your journey smoother, more comprehensible. Trust me, you don’t want to jam your brain figuring out React’s intricate lore without grasping JavaScript. It’s like finding your way around without a map. Do you really want that?

Foundational Blocks of JavaScript for React

Variables and Objects in JavaScript

Churning the wheels of JavaScript, we encounter variables and objects. They work side-by-side in your code, storing and managing information. Here’s a var example: var foo = "hello world!"; Variables, specific kinds of data types, are perfect for holding your data, altering with time. They come in flavors such as ‘var’, ‘let’, and ‘const.’ While ‘var’ unfolds itself in the global scope, ‘let’ and ‘const’ maintain local discretion! Here is how you can use them:

var foo = "hello world!"; 
let bar = "Hey, There!"; 
const baz = "What's up?";

As we advance, we step into the realm of object destructuring. Take a look at this:

let gfg = { 
   fullName: "GeeksforGeeks" ,
   type: "eduTech" , 
   location: "Noida" 
} 
let {fullName: CompanyName, location: cLocation}=gfg; 
console.log(gfg);

By using object destructuring, data extraction from an object becomes effortless and neat. It is a powerful tool, particularly pertinent for React’s Function Components, turning JavaScript navigation into a smooth sail. Marvelous, isn’t it?

Functions and Arrow Functions

JavaScript functions, aren’t they amazing? Brewing your logic, brewing your code with the function keyword and function parameter! But we have a new kid on the block, arrow functions. These arrow function components offer you a neater, more concise syntax. Just like our old friends, but with an added allure!

Want a taste of the traditional function? Here you go:

function greeting() { return 'hello'}

console.log(greeting()) // hello

But the Arrow Function, built without a ‘this’ or function keyword – now, that’s a different story:

let greeting = () => 'hello'

console.log(greeting()) // hello

Same result, cleaner syntax with better use of parentheses. And remember, unlike normal functions, arrow functions do not have names. This characteristic sets your code on fire! Can’t wait to use them, can you? I bet you’re thrilled and so am I! Plus, if you’re dabbling in React, understanding these callback functions is crucial as React makes extensive use of them. Now get out there and start coding with style!

Array Methods

Oh, the joy of JavaScript Array methods! Helping you juggle data in your arrays, they play a crucial role. Array destructuring, for instance, is a gem in the crown of JavaScript Array methods. Need to create a new array or extract values? Get your hands dirty with map() or the astounding power of array destructuring!

Example of Array Destructuring:

const vehicles = [ 'Swift' , 'Blackhawk' , 'Fortuner' ];

const [car, truck, suv] = vehicles;

console.log( "Truck is" , truck);

Or perhaps slip through each element with filter? Say hi to filter(). Let’s delve deeper!

How about doubling our numbers, eh?

const numbers = [2, 3, 4, 6];

const newArr = numbers.map(num => num * 2);

console.log(newArr); //4,6,8,12

And filtering out some unwanted guests?

const arr = [2,3,4,6];

const newArr = arr.filter(num => num > 3);

console.log(newArr); //4,6

Magic, isn’t it? The secret sauce to data manipulation in JavaScript! From map and filter to the exciting world of array destructuring, trust me, you’ll use them all the time in React!

Promises and Async/Await

Promises and Async/Await? Now, we’re moving to the deep end. Complexity not intended, but a promise in JavaScript is essentially… a promise. It says, “Hey, I might take some time, but I’ll get your stuff sorted!”

Async/Await? These kids make handling promises easier! Let’s get our heads around it:

async function fetchData() {

    const response = await fetch('https://api.example.com/data');

    const data = await response.json();

    return data;

}

Hey, Voila! If you successfully fetched the data, we process and return it otherwise catch the error. Async/Await and promises in harmony.

JavaScript Syntax Essential to React

Destructuring

Next up, destructuring – yet another charming feature of JavaScript. It simplifies extracting values from arrays or objects like a breeze, through a superb application of the property shorthand concept. Seriously, the older way of doing this:

const student = { 'name': 'Mary', 'age': 15}

const name = student.name; //Mary

const age = student.age; //15

Turns into the cooler, shorthand version:

const {name, age} = student; //Mary, 15

Shorter, precise – beautiful! Embrace destructuring with open arms, it’s a relief and a testament to the power of property shorthand – you’ll thank later!

Template Literals

Template literals, folks! Javascript back-tick revolution. These allow for embedding expressions in your string literals. Gives your strings a mega-boost!

Typical concatenations like:

console.log('Hello' + ' ' + 'World' + '!') //Hello World!

Simply turn into delicious simplicity:

console.log(`${'Hello'} ${'World'}!`) //Hello World!

Who knew you could bake flavor into strings, eh? Now, you do! Template literals, welcome aboard the JavaScript Express!

Rest/Spread Operators

Remember the three dots ...? Yes, we found them in rest and spread operators! Mischievous twins, but their roles? Starkly different.

Rest operator? Gathers your elements into an array. Spread operator on the contrary, lets your array strut in style, spreading its elements.

Observe this showtime:

// Spread operator

const arrayOne = [1, 2, 3];

const arrayTwo = [4, 5, 6];

const arrayThree = [...arrayOne, ...arrayTwo];

console.log(arrayThree); // 1,2,3,4,5,6

// Rest operator

const [first, ...rest] = arrayThree;

console.log(first); // 1

console.log(rest); // 2,3,4,5,6

Forgot copy-pasting arrays! All thanks to our dear spread operator. Rest, meanwhile, making it possible to extract multiple elements with ease. JavaScript can surprise you, can’t it?

Short Conditionals

Finally, short conditionals – the quick and snappy decision-makers in JavaScript. Include && (and), || (or), and the ever-fancy Ternary Operator. Shorter expressions of conditions than the usual if/else statements.

Let’s catch all this action in React:

const isLoggedIn = true; return isLoggedIn ? "Welcome back!" : "Who are you?";

Can you see it in action? If the user is logged in, it welcomes you back, or else, it queries you with “Who are you?”. This is the beauty of JavaScript short conditionals, and since they are dynamic and their value can change at runtime, it means they’re compact and to the point. Learn more about such functional means, and your flow with React, a component-based library, will be smoother than ever!

Getting Familiar with React Essentials

Understanding React Elements

Stepping into the React terrain, we first encounter the React elements. The fundamental bricks in your React application. They’re like the Lego blocks, you know? Fitting perfectly with each other, creating magic!

Check this out:

const ele = <h1>Hello World!</h1>;

Here, <h1>Hello World!</h1> is a React element. Remember, it’s immutable. Oh, don’t confuse it with the HTML or DOM element. It’s simple, lean and professional like a corporate employee.

Sounds fun? It is! Ready to build your Lego castle? I hope so!

Exploring React Components

React Components – the heroes of our story! They are JavaScript functions, can’t be simpler, right? Class components, functional components, lots of types.

Recall this example component we had – “Welcome”:

import React from 'react';

function Welcome(){

    return <h1>Welcome to React!</h1>;

}

export default Welcome;

Components return HTML code sprinkled with dynamic values. Like your favorite pizza, topped with veggies and oozing cheese! They are the true powerhouses of React. Building blocks of your UI, putting together the magic you see on your screen. Long story short, in React, components are the rockstars!

Ready to jam with them? Push up your sleeves, let’s get the show on the road!

Implementing JSX Expressions

Implementing JSX expressions, you say? In React, JSX equals love! It’s the secret ingredient of your UI recipe. JSX – a HTML-JavaScript hybrid. Our favorite cocktail!

This is your classic JSX expression:

const heading = <h1>Mozilla Developer Network</h1>;

Psst. Remember, you can only return a single parent element from a JSX function.

const header = (
  <header>
    <h1>Mozilla Developer Network</h1>
  </header>
);

Oops! Pure HTML won’t run in JavaScript land. We need a translator. Here comes React.createElement(), translating our JSX into React elements, readable by our browser!

JSX expressions – the heart and soul of your React application, pumping life into your UI! Get fluent in them; your journey in React rides on it! Ready to deep dive? Let’s roll!

Starting Your Journey with React

Setting up your First React App

Setting up your first React app? The anticipation is palpable, isn’t it?

Remember our study on Node.js, the indispensable stepping stone to start app development with React? So first, ensure Node.js is installed:

node -v

Do you see your version number? Brilliant, time for the next step. Now, conjure up a fresh React app with the following mystical command:

npx create-react-app hello-world

And voila, your premier React app, hello-world, is primed and ready for action! Delve into it using your code editor of choice (Visual Studio Code is a personal preference), and with a little manipulation:

npm run start

Your app is now surfing the waves of the browser, running localhost:3000. Bask in the familiar warmth of ‘Hello World’ once again!

Tip: Familiarize yourself with the structure. The public folder is where index.html resides – the course your browser feeds on. All your logic, styling, and markup are snugly tucked away in src. As your root component, App.js is a crucial place to start with app development – make modifications, save.

Setup concluded! Gear up, let’s invoke some magic in the realm of app development!

Building Accessible Components with React 18

Remember how important accessibility is in web development? Yes, and introducing UI design can elevate this even more. Time to build accessible, well-designed components with the fabulous React 18!

Find your rhythm, use semantic HTML – they’re not mere suggestions, folks! All interactive elements – imagine buttons, links, form fields – are designed and coded to be accessible right out of the box. How?

Ever heard of ‘ARIA’? It’s a crucial part of our UI design toolkit, helping us – supercharge HTML to convey everything to assistive technologies!

Need to add custom functionality, labels, or roles? Sure, integrating UI design principles would help here too. Give this a whirl:

<input
  type="search"
  name="q"
  placeholder="Enter text"
  aria-label="Please enter your desired text." />

And bam, with UI design and React 18 working hand in hand, your component now ensures a smooth, user-friendly digital experience for all!

React, making your life easier and a wonder with UI design, one component at a time! Want to dive deeper into the world of React and UI design? Strap in and get ready for the dive!

Creating User Interfaces from Components

Creating User Interfaces with components, the essence of React! This is where the magic of component logic comes into play. Remember the Lego analogy? Yes, you’re building a beautiful castle, one component at a time!

Imagine, UI – a big complex task. Each component, a clickable jigsaw piece with encapsulated logic, ultimately affecting output. Your job, fit it together. You don’t break a sweat in this. React does it, updating the right components when your data changes, reflecting a well-maintained output. This component logic provides a well-structured, modular approach.

Feeling satisfied with your component assembly line? It’s time to test it! React provides you with Jest, a handy tool for testing every component and its expected output.

Getting close to the React dream, eh? High fives! Keep pushing!

Diving Deep with React

Introducing React Hooks

Roll up your sleeves, friends! Time to grasp React Hooks and its mighty state data handling capabilities. First unveiled with the launch of React 16.8 in February 2019, it has been a game-changer indeed. Hooks pave the way for us to bypass the classic classes, hooking directly into React state data and lifecycle features from function components – reminiscent of ‘state: {data: null}’ style in React classes. They truly are, in a sense, the cutting-edge!

Remember useState and useEffect, the chart-toppers? Originally devised for mastering state data and side effects respectively, they have always been at our rescue.

However, it comes with a word of caution – the rules!

1. “Only Call Hooks at the Top Level”
2. “Only Call Hooks from React Functions”

Tread carefully on this path, my friends. It’s more than just a thrilling ride! Equipped with this knowledge, let’s break into this power-packed world of hooks and their state data manipulation abilities!

Enhancing React Developer Tooling

As we delve deeper into React, your developer toolkit grows. This is primarily because of the importance of understanding JavaScript modules before mastering React modules. Streamline your workflow and boost productivity with upgraded dev tools.

Visual Studio Code, my favourite, works brilliantly with React module. It’s smart, lightweight, with top-notch features and extension support: Autocompletion (intellisense), live server, Git integration, debugging – an impressive list indeed!

React Developer Tools extension, a pure charm for managing the React module. Excel at inspecting and debugging your React components—check out the Component and the Profiler tabs for notable time-saving strategies.

Code formatters like Prettier, ESLint spot and fix your code. They help maintain your code and ensure that JavaScript modules are being used, which are crucial for an organized coding environment. Combine these with Husky and lint-staged for an airtight workflow.

In a nutshell, understanding modules, especially React modules, and proper tooling in React, sharpens you, equipping you to produce superior quality code! So pack your toolkit, and jump right in, the water’s warm!

Getting to Know Server Components

Server components, or RSCs, are the latest buzz in the React world! These cool dudes run exclusively on the server. Unlike their brothers, the Client-side Components, they rule out any JavaScript to your client-side.

Imagine this – RSCs cozily fetch your data from the server, sending HTML content straight to your cozy browser. No hydration happening here!

Started as experimental, but Next.js is already taking them for a joyful ride!

RSCs are like an experimental music band. Might not be mainstream yet, but sure got potential to become the next big thing.

RSCs, adding another feather to the React cap! Ready to rock and roll with them? I am, too! Let’s ride this wave together!

Adding Interactivity Wherever You Need it

What’s an app without interactivity? Dead as a dodo! With React, an essential app component, you’ve got the power to pepper interactivity wherever you want! Be it a tiny part of the page, or the whole, input of React can spice it up with life! You could have several independent React instances sprinkled across your site, each carrying its uniqueness.

Using JSX, an effective tool for the job, we build an interactive interface. Let’s picture a selection of animal images, for instance. Users can click an image for a fun fact. Now, witness the magic:

function AnimalFact({image, fact}) {
    return <img src={img} onClick={alert(fact)} />;
}
...
<AnimalFact image={animal1} fact={fact1}/>
<AnimalFact image={animal2} fact={fact2}/>

Impressive, isn’t it? A simple user input, and we, the app component, pop up an intriguing fun fact. That’s the power of React in creating interactive UIs!

React – turning your dreams of interactive UIs into reality! Let’s co-create this magic. Ready, set, React!

Conclusion

Why Learn ReactJS?

Why learn ReactJS, you ask? Well, there are numerous exciting reasons! Easy to grasp, it has friendly documentation, endless online resources, and an intuitive app function that you can easily get the hang of. Got basics of JavaScript? Great, you’re already halfway on the road of mastering ReactJS!

Famed for its reusable components, ReactJS is a real lifesaver when dealing with repetitive code. Say goodbye to duplications and embrace the perfect system for DRY (Don’t Repeat Yourself). This significantly saves your time and effort!

What about employment prospects? Countless top-tier companies hover over React much like a bee over nectar. LinkedIn, Instagram, Facebook, Twitter, Airbnb— the list’s endless! A solid understanding of React and sure grasp of reactdom operation? That’s your premium ticket to plentiful job opportunities!

Giving a notable performance boost, React is indeed the star of our show, featuring the speedy Virtual DOM. It makes rendering pages lightning-fast, taking the load off your shoulder!

Talking about flexibility and extendibility, React is in a league of its own. It’s such an elegant tool, empowering developers to design their style and efficiently manage dependencies in the coding process. Pick and match your own libraries, design systems!

React, the darling of front-end web development, isn’t just a reprised coding language but a must-have arsenal on your learning journey! Its skyrocketing popularity is no surprise— there’s no stopping a well-prepared React developer armed with the right skillset. So, what are you waiting for? Let’s dive in at once!

Becoming a Professional React Developer

Becoming a professional React developer – it’s no walk in the park, buddies! But then, what’s worthwhile without a good challenge, right?

First things first, build a strong base with JavaScript, HTML, and CSS! React leans on JavaScript, so make sure you’re good friends!

Brush up the React basics – components, props, state, and lifecycle. Never underestimate them. They lay the foundation of everything React!

Want to level up? Get your hands dirty with advanced topics: Context API, Redux, or the star, Hooks!

Always remember, practice! Construct projects benefits beyond reading tutorials and documentation.

And of course, network. Join local meetups, online communities, follow leading React developers on Twitter. It helps to stay updated, get new ideas!

Finally, a solid portfolio. Show off your projects, even contribution to open source. It’s your golden ticket to job interviews!

It’s a journey, folks! Ups and downs, highs and lows. Patience, my friend, the results will blow you away. Let’s hop on this ride to success!

FAQs

What are the Top Important JavaScript Concepts to know before learning Reactjs?

Ah, the concepts you need to grasp JavaScript prior to jumping into React. They’re critical! Begin with understanding Variables and Objects, and meet our star players- ‘var’, ‘let’, and ‘const’. Get a handle on Functions and Arrow functions, which promise a concise and cleaner syntax, akin to the class syntax introduced in ECMAScript 2015(ES6).

Array methods like map() and filter() serve as your essential toolkit to manipulate data. Have you ever heard about Promises and Async/Await? It’s time to know them; they assist in managing asynchronous operations in your code! The JSX syntax, akin to HTML but not quite, provides a smoother compilation step, like class syntax, its familiarity makes it easier to handle.

Finally, get comfortable with destructuring, template literals, rest/spread operators, and short conditionals. They help you write efficient and eloquent JavaScript that’s easily digestible by the compiler during the compilation phase. Quite an exposition, huh? But don’t worry, every step fortifies your journey with React.

The thrill of learning is unrivalled. Remember, the journey towards mastering the intricately woven web of ReactJS is as rewarding as the destination itself! Happy learning!

Is React Framework easier than JavaScript?

React, easier than JavaScript? My friend, React *is* JavaScript! A medley of its best features, skilfully assembled for building user interfaces.

Easiness is quite deceptive. Simple JavaScript operations might seem like a cinch. But try building anything larger, JavaScript might leave you swamped and sweating.

Now, take a stroll into React. Solving complex problems elegantly, thanks to its component-based architecture and the fantastic JSX – making code cleaner, simpler to understand.

The React magic – making JavaScript easier to work with! So, the question is more like: Is it easier to build web apps with React than Vanilla JavaScript? Definitely, yes!

Got a knack to learn? Onwards, to the React journey!

Can I learn ReactJS in 10 days?

Learn ReactJS in 10 days? You’re an enthusiast, I see!

Indeed, the foundational concepts like JavaScript basics, React fundamentals such as components, props, state, and the integral employment of jsx const can be learned. Experimenting with create-react-app and building a simple project? Absolutely possible if you put your heart and mind into it!

However, when it comes to mastering the intricate aspects of React like Redux, Context API, React Router, hooks, lifecycle methods, server-side rendering, and testing, that’s a whole different arena.

Remember, genuine learning isn’t cramming; it’s about understanding, implementing, and experimenting. Efforts, errors, and elevated insights are the stepping stones. So take your time.

As the age-old adage goes, Rome wasn’t built in a day, right? The same principle rings true for mastering React. 10 days might suffice for a sprint; the complete marathon, however, definitely takes time!

So, pull up your socks, put on your thinking hats, and break a leg. Remember, the sky’s the limit. Let’s sprint together in exploring ReactJS!