In React, you can create distinct components that encapsulate behavior you need. Then, you can render only some of them, depending on the state of your application.
Conditional rendering in React works the same way conditions work in JavaScript. Use JavaScript operators like [`if`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else) or the [conditional operator](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Conditional_Operator) to create elements representing the current state, and let React update the UI to match them.
Consider these two components:
```js
function UserGreeting(props) {
return <h1>Welcome back!</h1>;
}
function GuestGreeting(props) {
return <h1>Please sign up.</h1>;
}
```
We'll create a `Greeting` component that displays either of these components depending on whether a user is logged in:
It will render either `<LoginButton />` or `<LogoutButton />` depending on its current state. It will also render a `<Greeting />` from the previous example:
While declaring a variable and using an `if` statement is a fine way to conditionally render a component, sometimes you might want to use a shorter syntax. There are a few ways to inline conditions in JSX, explained below.
You may [embed expressions in JSX](/docs/introducing-jsx.html#embedding-expressions-in-jsx) by wrapping them in curly braces. This includes the JavaScript logical `&&` operator. It can be handy for conditionally including an element:
Note that returning a falsy expression will still cause the element after `&&` to be skipped but will return the falsy expression. In the example below, `<div>0</div>` will be returned by the render method.
Another method for conditionally rendering elements inline is to use the JavaScript conditional operator [`condition ? true : false`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Conditional_Operator).
In the example below, we use it to conditionally render a small block of text.
```javascript{5}
render() {
const isLoggedIn = this.state.isLoggedIn;
return (
<div>
The user is <b>{isLoggedIn ? 'currently' : 'not'}</b> logged in.
</div>
);
}
```
It can also be used for larger expressions although it is less obvious what's going on:
Just like in JavaScript, it is up to you to choose an appropriate style based on what you and your team consider more readable. Also remember that whenever conditions become too complex, it might be a good time to [extract a component](/docs/components-and-props.html#extracting-components).
In rare cases you might want a component to hide itself even though it was rendered by another component. To do this return `null` instead of its render output.
In the example below, the `<WarningBanner />` is rendered depending on the value of the prop called `warn`. If the value of the prop is `false`, then the component does not render:
Returning `null` from a component's `render` method does not affect the firing of the component's lifecycle methods. For instance `componentDidUpdate` will still be called.