React is an open-source JavaScript library for building user interfaces. It’s often compared to Flux, AngularJS or Backbone.js. The main purpose of React is to provide a consistent and predictable way to build web applications with minimal code. It uses a virtual DOM to manage how your application should behave at any given time, which makes debugging much easier React js Tutorial for Beginners – Step by Step- 2028
What is React?
React is a JavaScript library for building user interfaces. It uses a declarative approach to bind views and components together, allowing you to define what should be displayed in your app and how it should look.
React allows you to create reusable components which can be mixed and matched with other components or even modules from external sources without modifying the core of your application codebase.
In this ReactJS Tutorial for beginners, you will learn ReactJS step by step:
- What is ReactJS?
- Features of ReactJS
- Advantages of ReactJS
- Disadvantages of ReactJS
- Using ReactJS from CDN
- Using NPM Packages
- What is JSX?
- What are Components in ReactJS?
- What is a State in ReactJS?
- What are Props in ReactJS?
- Life Cycle of a Component
- Working Example
- Working with Forms
- Working with Events in ReactJS
- Working with Inline CSS in ReactJS
- Working with External CSS in ReactJS
Why use React over other JavaScript libraries and frameworks?
React is a JavaScript library that makes it easy to build user interfaces. It’s used by Facebook, Twitter, and many other companies.
In this article we’ll be looking at how you can use ReactJS to create your own personal website or app. React js Tutorial for Beginners
JSX Syntax
JSX is a JavaScript syntax extension, not a new language. It’s not a preprocessor like CoffeeScript or Sass, nor does it provide any templating capabilities.
JSX allows you to write your React code using HTML-like constructs that resemble the markup of your app’s UI. If you’ve ever used Angular 2 or Vue, then you’ll be familiar with this approach (though they use JSX syntax rather than plain old HTML).
Variables, Data Types and Operators
Variables are one of the most important concepts in any programming language. They’re used to store data in memory and refer to that data later on.
Data types define how a variable will be stored and what can go into it (or not). For example, a Boolean variable stores only two values: true or false, but if you want your program’s output to show whether something is true or false, you would need an integer type instead because integers can handle numbers rather than just boolean values.
Operators perform mathematical operations on variables; these include addition (+), subtraction (-), multiplication (*), division (/), modulo (%) and exponentiation ^(+).
Loops, Iterations and Recursion
Loops are statements that repeat a block of code while some condition is true. To loop over a collection, use the for statement:
//Looping over all elements in array
for (var i = 0; i < array.length; ++i) {
//Do something with each element }
The first argument to the for statement is the variable index or value you want to iterate over and then assign it to an object variable called i . In this case, we’re iterating from 0 until our array has been completely traversed. If you have 1 million elements but only need 200 of them, then your loop will finish after those 200 items have been processed!
The next thing you’ll probably notice about loops is how they work with arrays: if there are any duplicates in your array (e.g., multiple entries for an ID column), then each iteration will fill up with duplicate data until no more duplicates exist anymore–then get rid of all but one copy by simply assigning them all into one object variable called “a”. This way when we try printing out just one entry per iteration instead of having everything printed out as part of how things happen inside such statements like this one…
Conditional Statements and Boolean Expressions
In JavaScript, you can use the if, else and switch statements to write code that’s more readable. For example, if you want to add a number of users to your application using the create() method on an object called User, then you would write:
“`javascript
var user = { name: ‘John’, email: ‘johndoe@example.com’ };
if (user.create()) { // do something with user } else { // don’t do anything }“`
Array Functions (forEach, map, reduce, filter)
ForEach
ForEach is a function that takes a variable and does something to it. The following code will create an array of strings which are the same as the original array:
var myArray = [];
for (var i = 0; i < 100; i++) { myArray[i] = “Hello World!” } //outputs: [“Hello World!”, “Hello World!”, “Hi”, “there!”, “world!”]
Functions, Promises and Async/Await
Async/Await is a new feature in JavaScript that allows you to write asynchronous code that looks synchronous. It makes it easier to read and reason about your code, while also making it easier to write tests for asynchronous code.
It works by wrapping any function with async() or await(), then having the function invoke an external function (or set of functions) on completion of its task.
Classes, Inheritance, Prototypes and this keyword in JavaScript
- Classes, inheritance and prototypes are three powerful tools for structuring your code.
- Classes: Classes are used to create objects that can be used in other parts of the program. This is how you define classes in JavaScript:
- class Person { name; age; }
- Inheritance: Inheritance allows a class to inherit from another class by using the extends keyword. For example:
- class Person extends Animal { }
Events Handling with React.js (onClick, onChange)
Events handling with React.js (onClick, onChange)
OnClick: The event handler will be fired when the user taps or clicks on an element.
OnChange: The event handler will be fired whenever the value of a field changes. This can happen when you type something into a text box, select an option from a drop down list or change the contents of an input box using keyboard shortcuts. For example, if you have an input field and type something in its text box then this event is triggered once again after each character that you write in that spot! So don’t forget to add it!
Learn How to Use React
React is a JavaScript library that lets you build user interfaces. It’s a great way to build complex single-page applications (SPAs) with minimal effort, and it has the advantage of being able to run on any browser.
You can use React in many ways, but we’ll focus here on creating simple web apps using React. The first step is learning how to get started with this framework by building an app called “Hello World!”
In this tutorial, we learned the basics of React.js and how to use it with real-world examples. We covered the topic from JavaScript fundamentals up to advanced topics like dealing with asynchronous functions and working with classes in JavaScript. React js Tutorial for Beginners – Step by Step- 2028 React js Tutorial for Beginners