What is the purpose of the && operator in conditional rendering?

The JavaScript conditional rendering concept allows you to display content in a dynamic way, based on predetermined conditions. The logic AND operator is often used to simplify code and improve readability for conditional rendering. This article will examine the purpose of && operator conditional rendering, and how to apply conditional rendering in JavaScript applications.

Prerequisites:

• JavaScript
• React
• NPM and node installed.

The && operator is primarily used for evaluating multiple conditions within an if statement. It returns true if and only if both of its operands are true; otherwise, it returns false. In the context of conditional rendering, the && operator allows you to combine multiple conditions to determine whether a particular component or piece of content should be rendered.

Syntax:

condition && expression

Steps to Create a React application:

Step 1: Create a ReactJS project:

npx create-react-app conditional-rendering

Step 2: Navigate to the project:

cd  conditional-rendering

Project Structure:

Project structure

Dependencies:

"dependencies": {
    "@testing-library/jest-dom": "^5.16.4",
    "@testing-library/react": "^13.2.0",
    "@testing-library/user-event": "^13.5.0",
    "bootstrap": "^5.1.3",
    "react": "^18.1.0",
    "react-dom": "^18.1.0",
    "react-icons-kit": "^2.0.0",
    "react-redux": "^8.0.2",
    "react-scripts": "^5.0.1",
    "redux": "^4.2.0",
    "web-vitals": "^2.1.4"
}

Approach to use && operator:

• From the React library, the useState hook is imported. It’s the hook that allows you to have state variables in functional components.
• A state variable ‘showText’ shows whether the content is visible or hidden.
• A ‘setShowText’ function is used to update the current state value of ‘showText’ variable.
• useState(true) assigns the state variable ‘showText’ with the boolean value where it is true initially.
• The UI of the component is represented by a JSX structure.
• Based on the value of ‘showText’ state variable, content shall be conditionally rendered. The Lorem Ipsum text will appear if ‘showText’ value is false.
• An onClick event handler calls the ‘textVisibility’ function when you click this button element. Based on the currently displayed value of showText, the text in the button will be changed.

Example: A Simple React component demonstrating the functionality of hiding and displaying content by clicking a button is provided in this code. To manage the visibility state, it uses the useState hook, which updates the UI dynamically.

Javascript

//App.js

import { useState } from "react";
import './App.css';

export default function App() {
    const [showText, setShowText] = useState(true);

    const textVisibility = () => {
        setShowText(!showText);
    };

    return (
        <div className="App">
            <center>
                {!showText && (
                    <p>
                        React is very simple and user friendly.
                        It does not have a presefined structure.
                        It just uses JavaScript and JSX to
                        create the Single page Application.
                        If you have the basic knowledge of HTML,
                        CSS and JavaScript you are good to go to dive
                        deep into the React world.
                    </p>
                )}
                <button onClick={textVisibility}>
                    {showText ? "Show some text" : "Hide it"}
                </button>
            </center>
        </div>
    );
}

CSS

/* App.css */

.App {
    font-family: sans-serif;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 90vh;
}

button {
    color: white;
    background-color: black;
    padding: 10px 20px;
}

Output: