react-spring/docs/app/routes/docs.concepts.targets.mdx

---
meta:
  title: Targets | React Spring
  'og:title': Targets | React Spring
  'twitter:title': Targets | React Spring
  description: An in-depth conceptual guide to react-spring targets and how to make your own.
  'og:description': An in-depth conceptual guide to react-spring targets and how to make your own.
  'twitter:description': An in-depth conceptual guide to react-spring targets and how to make your own.
  'og:url': https://www.react-spring.dev/docs/concepts/targets
  'twitter:url': https://www.react-spring.dev/docs/concepts/targets
sidebar_position: 4
---

import { formatFrontmatterToRemixMeta } from '../helpers/meta'

export const meta = formatFrontmatterToRemixMeta(frontmatter)

# Targets

## What is a target?

When a target is discussed it is sometimes in reference to the platform, e.g. you create a client side react application
chances are it's targeted at the browser. However, if you write a server-side application then you're targeting node.
Whilst `react-spring` does support the targets `web` and `native` and _can_ be server-side rendered. This is not the type
of target we're referring to.

A target in `react-spring` is a `react reconciler` a.k.a `react renderer`. That is, a custom renderer that can process different
JSX components, it's duty is to create / update and remove these elements from the browser. `react-dom` is a prime example of
a `reconciler`, it handles DOM elements _exclusively_ and understands how to apply attributes to those DOM nodes via react `props`.

Therefore, in `react-spring` we have the following targets that correspond to their respective reconcilers:

- `web` - `react-dom`
- `native` - `react-native`
- `three` - `react-three-fiber`
- `konva` - `react-konva`
- `zdog` - `react-zdog`

To download a target you can use the `@react-spring/[target]` format:

```bash
yarn add @react-spring/web
```

## Adding a target

To create your own target, we offer the `createHost` function. This function returns the `animated` components related to the
specific target, e.g. the host created in `@react-spring/web` returns the animated dom components such as `animated.div`.

The signature for `createHost` function looks like this:

```ts
type CreateHost = (
  components: AnimatableComponent[] | { [key: string]: AnimatableComponent },
  config: Partial<HostConfig>
) => {
  animated: WithAnimated
}
```

### AnimatableComponent

The first argument `AnimatableComponent[] | { [key: string]: AnimatableComponent }`, is a list of strings that relate the native
elements of the renderer you're targeting. Using the same example of `@react-spring/web`, the components would include the strings
`'div', 'li'` etc. These components are then created into `Animated` components in the `createHost` function via the `withAnimated`
HOC.

### HostConfig

```ts
interface HostConfig {
  /** Provide custom logic for native updates */
  applyAnimatedValues: (node: any, props: Lookup) => boolean | void
  /** Wrap the `style` prop with an animated node */
  createAnimatedStyle: (style: Lookup) => Animated
  /** Intercept props before they're passed to an animated component */
  getComponentProps: (props: Lookup) => typeof props
}
```

Whilst the entire config object is wrapped in `Partial`, meaning that the keys are optional, realistically `applyAnimatedValues` is
required. This is the logic for how the `Animated` components apply their `SpringValues`, this typically would come from the reconciler
either attached to the `instance` in the case of `react-konva` or an exported function like in `@react-three/fiber`.

The `createAnimatedStyle` key of the config object by default takes wraps the `style` prop in an `AnimatedObject` instance which has
generic rules on applying keys. In the case of `@react-spring/web`, we pass a custom function which is how we support shorthands for
transformation styles.

The getComponentProps is a middleware function that allows you to intercept props before they're passed to the animated component, therefore
you could omit props e.g. `scrollTop` for the web because `@react-spring/web` expects this to be in the `style` object.

For more information on `animated` elements, see [here](/docs/concepts/animated-elements).