1. reactjs-components

ReactJs Components

ReactJs is a popular JavaScript library that allows developers to create efficient and reusable user interface components. ReactJs components can be defined as independent, reusable pieces of code that are responsible for rendering a portion of a user interface. In this page, we will discuss the basics of ReactJs components.


The syntax for creating a ReactJs component is:

class ComponentName extends React.Component {
    render() {
        return (
            // JSX code goes here


Let's create a simple ReactJs component that renders a "Hello World" message:

class HelloWorld extends React.Component {
    render() {
        return (
                <h1>Hello World</h1>


When we render the HelloWorld component, we will see the following output:

Hello World


In the above example, we created a class named HelloWorld that extends the React.Component class, which gives us access to various ReactJs functionalities. Inside the render() method, we defined the user interface component using JSX syntax, which allows us to write HTML-like syntax in our JavaScript code. The render() method must always return a single element.


ReactJs components can be used in any web application. To use the above HelloWorld component, we can create a new ReactJs element in our main application file:

    <HelloWorld />,

In the above example, we used the ReactDOM library to render our HelloWorld component within a div with the ID of "root".

Important Points

  • ReactJs components are reusable and composable building blocks for web applications.
  • It is important to define a render() method in a component that returns a single element.
  • Components can be passed props (or properties) which allow for more customizable components.


ReactJs components are an essential part of building web applications using ReactJs. They allow developers to create reusable and efficient user interface components that can be used in any web application. By following the syntax and example provided above, you can easily create your own ReactJs components and use them to create your own web applications.

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