What is React Elements

• In ReactJS, a "React element" is a simple, lightweight object that describes a component's markup and attributes. It is the smallest building block of a React application, and is used to define the structure and content of a component.

• React elements are often created using JSX syntax, which makes it easy to write and read HTML-like code in JavaScript files. For example, the following JSX code creates a React element that represents a "h1" tag with the text "Hello, world!":

const element = <h1>Hello, world!</h1>;

• Under the hood, JSX is transpiled into JavaScript code that uses the "React.createElement" function to create a React element. Here's how the previous example would look like after being transpiled:

const element = React.createElement("h1", null, "Hello, world!");

• React elements are often used in combination with other React elements and components to build a complex user interface. For example, the following JSX code creates a React component that uses two child components to render a form:

function MyForm() {

    return (

        <form>

            <MyInput label="Name" />

            <MyInput label="Email" />

            <button type="submit">Submit</button>

        </form>

    );

}

• In this example, the "MyForm" component uses two "MyInput" components to render form fields for the user to enter their name and email. The "button" element is also a child of the "form" element.

• React elements are immutable, meaning that they cannot be modified once they are created. Instead, you can create a new element with updated properties and pass it to the "ReactDOM.render" method to update the user interface.

• In summary, a React element is a simple, lightweight object that describes a component's markup and attributes. It is the smallest building block of a React application, and is used to define the structure and content of a component.