Conditional Rendering

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Render different UIs depending on different conditions and states

React Hooks Handbook

Intro to React Hooks

3:39

Create your first React app

4:23

React Component

2:54

Styling in React

5:06

Styles and Props

2:22

Understanding Hooks

3:21

useState Hook

2:54

useEffect Hook

3:41

useRef Hook

3:00

Props

3:11

Conditional Rendering

4:21

Load Local Data

4:04

Fetch Data from an API

5:40

Toggle a state

4:05

useInput Hook

6:04

Gatsby and React

6:44

NextJS and React

5:24

React TypeScript Part 1

8:19

React TypeScript Part 2

7:35

useScrollPosition Hook

4:26

useOnScreen hook

8:08

useContext Hook

8:32

Fragments

2:43

Lazy Loading

4:05

React Suspense

3:13

Environment Variables

4:43

Reach Router

5:31

URL Params

4:04

SEO and Metadata

6:47

Favicon

3:03

Dynamic Favicon

2:14

PropTypes

3:54

Custom PropTypes

3:58

useMemo Hook

4:05

forwardRef Hook

3:28

Handling Events

5:44

Spread attributes

3:35

useMousePosition Hook

4:55

useReducer with useContext Part 1

7:33

useReducer with useContext Part 2

6:48

useReducer with useContext Part 3

5:43

Netlify

5:08

Gatsby Cloud

6:19

Gatsby Plugin Image

8:11

useOnClickOutside Hook

6:32

useWindowSize Hook

4:14

usePageBottom hook

4:48

useLocalStorage Hook

5:27

Three.js in React Part 1

17:33

Three.js in React Part 2

11:18

CodeSandbox link

You can find the full code for this tutorial at https://codesandbox.io/s/conditional-rendering-dpvzy.

Logical AND operator

The logical AND (&&) operator can be used to render different UIs depending on some conditions. Let's say we want to display a message saying You have 1 new notification only when the user has one notification or more.

Let's create our NotificationCard component. It'll simply be a text that will depend on the local state. Learn about useState in the useState Hook section of this handbook.

import React, { useState } from "react";

const NotificationCard = () => {
    const [notificationNumber, setNotificationNumber] = useState(1)

    return (
        <div>
            <p>You have {notificationNumber} new notification</p>
        </div>
    );
};

export default NotificationCard;

Then, we'll add a condition using the logical AND (&&) operator to only display the text when the notificationNumber is greater or equal to 1.

<Wrapper>
    {notificationNumber >= 1 &&
        <Paragraph>You have {notificationNumber} new notification</Paragraph>
		}
</Wrapper>

You can change the initial value of notificationNumber to 0 and the text will disappear.

const [notificationNumber, setNotificationNumber] = useState(0)

You can style your components by using the styled-components package in your project. Learn more about it in the Styling in React section of this handbook.

The final code for the NotificationCard with styling is:

import React, { useState } from "react";
import styled from "styled-components";

const NotificationCard = () => {
    const [notificationNumber, setNotificationNumber] = useState(1);

    return (
        <Wrapper>
            {notificationNumber >= 1 && (
                <Paragraph>You have {notificationNumber} new notification</Paragraph>
            )}
        </Wrapper>
    );
};

export default NotificationCard;

const Wrapper = styled.div`
    background: rgba(255, 255, 255, 0.6);
    box-shadow: inset 0 0 0 0.5px rgba(255, 255, 255, 0.6);
    border-radius: 30px;
    padding: 20px;
    width: 300px;
    display: grid;
    gap: 30px;
    justify-items: center;
    align-items: center;
`;

const Paragraph = styled.p`
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
    font-style: normal;
    font-size: 15px;
    line-height: 48px;
    text-align: center;
`;

If...else statement

With an if...else statement, we can specify a condition and then, do something depending on whether that condition is true or false. In the example below, we're showing the logout button depending on the value of isLoggedIn. If the user is logged out, we want to display the Login text. If the user is logged in, we want to display the Logout text. I'm using the useState hook to set the state.

import React, { useState } from "react";

const SignInButton = () => {
    const [isLoggedIn, setIsLoggedIn] = useState(true);

    if (isLoggedIn) {
        return <button>Logout</button>;
    } else {
        // If user is logged out
        return <button>Login</button>;
    }
};

export default SignInButton;

You can change the also initial value of isLoggedIn to false and the text will change to Login.

const [isLoggedIn, setIsLoggedIn] = useState(false)

You can style your components by using the styled-components package in your project. Learn more about it in the Styling in React section of this handbook.

The final code for the SignInButton with styling and using the if...else statement is:

import React, { useState } from "react";
import styled from "styled-components";

const SignInButton = () => {
    const [isLoggedIn, setIsLoggedIn] = useState(true);

    if (isLoggedIn) {
        return <Button>Logout</Button>;
    } else {
        // If user is logged out
        return <Button>Login</Button>;
    }
};

export default SignInButton;

const Button = styled.div`
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
    font-weight: bold;
    background: linear-gradient(91.4deg, #2fb8ff 0%, #9eecd9 100%);
    border: none;
    border-radius: 30px;
    box-shadow: 0px 20px 40px rgba(147, 231, 221, 0.3);
    cursor: pointer;
    display: grid;
    text-align: center;
    padding: 12px 0;
    width: 100%;
    position: relative;
    justify-content: center;
    max-width: 300px;
    margin: 0 auto;
    transition: 0.8s cubic-bezier(0.075, 0.82, 0.165, 1);
    color: white;
    font-style: normal;
    font-weight: normal;
    font-size: 17px;
    line-height: 130%;

    :hover {
        transform: translateY(-2px);
        box-shadow: 0px 20px 40px rgba(0, 0, 0, 0.15),
        inset 0 0 0 0.5px rgba(0, 0, 0, 0.3), inset 0 10px 40px rgba(0, 0, 0, 0.1);
    }

    :focus {
        outline: none;
    }
`;

Using ternary operators

An alternative to using an if...else statement is the ternary operator. This operator takes in three operands and is one of the most succinct ways to render something conditionally in React. We'll use the same example as above but use the ternary operator instead of the if...else statement.

const SignInButton = () => {
    const [isLoggedIn, setIsLoggedIn] = useState(true);

    return (
        <div>
            {isLoggedIn ? <button>Logout</button> : <button>Login</button>}
        </div>
        );
}

export default SignInButton

The result is exactly the same as the if...else statement, except that the code is cleaner and more readable.

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Conditional Rendering

Render different UIs depending on different conditions and states

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Toggle a modal visibility with a useOnClickOutside hook

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useWindowSize Hook

Create a hook to determine the width and height of the window

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usePageBottom hook

Detect if the user scrolled to the bottom of the page

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useLocalStorage Hook

Store an item in a browser's local storage

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Three.js in React Part 1

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