Conditional rendering is one of React’s most powerful features, enabling you to build dynamic, interactive user interfaces that respond seamlessly to user input and application state changes.

What Is Conditional Rendering in React?

In React, conditional rendering is the practice of displaying different elements or components based on specific conditions. Instead of updating the entire UI for every change, you can instruct React to render only the parts that need to change. This approach is not only efficient but also helps in creating cleaner, more maintainable code.

According to the official React documentation, conditional rendering works the same way conditions work in JavaScript—by using operators like if, the ternary operator (? :), or logical operators (&&, ||) to decide which elements to display

(legacy.reactjs.org).

Common Methods for Conditional Rendering

There are several techniques you can use in React. Let’s explore the most popular methods with examples.

1. Using If-Else Statements

The simplest way to render content based on a condition is by using plain JavaScript if...else statements. This is ideal when you have mutually exclusive cases.

function Greeting({ isLoggedIn }) {

if (isLoggedIn) {

return <h1>Welcome back!</h1>;

} else {

return <h1>Please sign up.</h1>;

}

}

When to use:

Use if-else when the logic is straightforward and the rendered components are entirely different. It’s clear and easy to read, especially in smaller components.

2. The Ternary Operator

The ternary operator is a shorthand for an if-else statement and is very popular within JSX.

const Greeting = ({ isLoggedIn }) => (

<div>

{isLoggedIn ? <h1>Welcome back!</h1> : <h1>Please sign up.</h1>}

</div>

);

When to use:

For simple conditions that result in one of two outcomes. However, be cautious with nested ternaries, as they can hurt readability.

3. Logical AND (&&) Operator

The logical AND operator is useful when you want to conditionally render a component only when a condition is true. It’s especially handy for optional elements.

const Mailbox = ({ unreadMessages }) => (

<div>

<h1>Hello!</h1>

{unreadMessages.length > 0 && (

<h2>You have {unreadMessages.length} unread messages.</h2>

)}

</div>

);

When to use:

Use && for conditions where you only need to render something if the condition is true, and nothing otherwise.

4. Switch Statements

For handling multiple conditions, a switch statement can make your code more organized and easier to read.

function RoleGreeting({ role }) {

switch (role) {

case 'admin':

return <h1>Welcome, Admin!</h1>;

case 'user':

return <h1>Welcome, User!</h1>;

default:

return <h1>Welcome, Guest!</h1>;

}

}

When to use:

When you have more than two conditions based on a single variable, a switch statement provides a clear, structured approach.

Real-World Use Cases

Conditional rendering is used in many parts of modern web applications. Here are a few examples:

Authentication:
Render a login form for unauthenticated users.
Display a user dashboard or profile page when the user is signed in.
Loading and Error States:
Show a loading spinner while data is fetched.
Display an error message if the data retrieval fails.
Role-Based Interfaces:
Differentiate between admin, editor, and viewer views.
Use switch statements or mapping objects to render appropriate components.
Dynamic Forms:
Render additional form fields based on user selections.
Enable or disable submit buttons based on input validation.