its-fine
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A collection of escape hatches for React.
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# its-fine
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[](https://npmjs.com/package/its-fine)
[](https://npmjs.com/package/its-fine)
[](https://twitter.com/pmndrs)
[](https://discord.gg/poimandres)
<p align="left">
<a id="cover" href="#cover">
<img src=".github/itsfine.jpg" alt="It's gonna be alright" />
</a>
</p>
A collection of escape hatches for React.
As such, you can go beyond React's component abstraction; components are self-aware and can tap into the [React Fiber](https://youtu.be/ZCuYPiUIONs) tree. This enables powerful abstractions that can modify or extend React behavior without explicitly taking reconciliation into your own hands.
## Table of Contents
- [Components](#components)
- [FiberProvider](#fiberprovider)
- [Hooks](#hooks)
- [useFiber](#useFiber)
- [useContainer](#useContainer)
- [useNearestChild](#useNearestChild)
- [useNearestParent](#useNearestParent)
- [useContextMap](#useContextMap)
- [useContextBridge](#useContextBridge)
- [Utils](#utils)
- [traverseFiber](#traverseFiber)
## Components
### FiberProvider
A react-internal `Fiber` provider. This component binds React children to the React Fiber tree. Call its-fine hooks within this.
> **Note**: pmndrs renderers like react-three-fiber implement this internally to make use of [`useContextBridge`](#usecontextbridge), so you would only need this when using hooks inside of `react-dom` or `react-native`.
```tsx
import * as ReactDOM from 'react-dom/client'
import { FiberProvider, useFiber } from 'its-fine'
function App() {
const fiber = useFiber()
}
ReactDOM.createRoot(document.getElementById('root')!).render(
<FiberProvider>
<App />
</FiberProvider>,
)
```
## Hooks
Useful React hook abstractions for manipulating and querying from a component. These must be called within a [`FiberProvider`](#fiberprovider) component.
### useFiber
Returns the current react-internal `Fiber`. This is an implementation detail of [react-reconciler](https://github.com/facebook/react/tree/main/packages/react-reconciler).
```tsx
import * as React from 'react'
import { type Fiber, useFiber } from 'its-fine'
function Component() {
// Returns the current component's react-internal Fiber
const fiber: Fiber<null> | undefined = useFiber()
// function Component() {}
if (fiber) console.log(fiber.type)
}
```
### useContainer
Returns the current react-reconciler container info passed to `Reconciler.createContainer`.
In react-dom, a container will point to the root DOM element; in react-three-fiber, it will point to the root Zustand store.
```tsx
import * as React from 'react'
import { useContainer } from 'its-fine'
function Component() {
// Returns the current renderer's root container
const container: HTMLDivElement | undefined = useContainer<HTMLDivElement>()
// <div> (e.g. react-dom)
if (container) console.log(container)
}
```
### useNearestChild
Returns the nearest react-reconciler child instance or the node created from `Reconciler.createInstance`.
In react-dom, this would be a DOM element; in react-three-fiber this would be an `Instance` descriptor.
```tsx
import * as React from 'react'
import { useNearestChild } from 'its-fine'
function Component() {
// Returns a React Ref which points to the nearest child <div /> element.
// Omit the element type to match the nearest element of any kind
const childRef: React.MutableRefObject<HTMLDivElement | undefined> = useNearestChild<HTMLDivElement>('div')
// Access child Ref on mount
React.useEffect(() => {
// <div> (e.g. react-dom)
const child = childRef.current
if (child) console.log(child)
}, [])
// A child element, can live deep down another component
return <div />
}
```
### useNearestParent
Returns the nearest react-reconciler parent instance or the node created from `Reconciler.createInstance`.
In react-dom, this would be a DOM element; in react-three-fiber this would be an instance descriptor.
```tsx
import * as React from 'react'
import { useNearestParent } from 'its-fine'
function Component() {
// Returns a React Ref which points to the nearest parent <div /> element.
// Omit the element type to match the nearest element of any kind
const parentRef: React.MutableRefObject<HTMLDivElement | undefined> = useNearestParent<HTMLDivElement>('div')
// Access parent Ref on mount
React.useEffect(() => {
// <div> (e.g. react-dom)
const parent = parentRef.current
if (parent) console.log(parent)
}, [])
}
// A parent element wrapping Component, can live deep up another component
;<div>
<Component />
</div>
```
### useContextMap
Returns a map of all contexts and their values.
```tsx
import * as React from 'react'
import { useContextMap } from 'its-fine'
const SomeContext = React.createContext<string>(null!)
function Component() {
const contextMap = useContextMap()
return contextMap.get(SomeContext)
}
```
### useContextBridge
React Context currently cannot be shared across [React renderers](https://reactjs.org/docs/codebase-overview.html#renderers) but explicitly forwarded between providers (see [react#17275](https://github.com/facebook/react/issues/17275)). This hook returns a `ContextBridge` of live context providers to pierce Context across renderers.
Pass `ContextBridge` as a component to a secondary renderer to enable context-sharing within its children.
```tsx
import * as React from 'react'
// react-nil is a secondary renderer that is usually used for testing.
// This also includes Fabric, react-three-fiber, etc
import * as ReactNil from 'react-nil'
// react-dom is a primary renderer that works on top of a secondary renderer.
// This also includes react-native, react-pixi, etc.
import * as ReactDOM from 'react-dom/client'
import { type ContextBridge, useContextBridge, FiberProvider } from 'its-fine'
function Canvas(props: { children: React.ReactNode }) {
// Returns a bridged context provider that forwards context
const Bridge: ContextBridge = useContextBridge()
// Renders children with bridged context into a secondary renderer
ReactNil.render(<Bridge>{props.children}</Bridge>)
}
// A React Context whose provider lives in react-dom
const DOMContext = React.createContext<string>(null!)
// A component that reads from DOMContext
function Component() {
// "Hello from react-dom"
console.log(React.useContext(DOMContext))
}
// Renders into a primary renderer like react-dom or react-native,
// DOMContext wraps Canvas and is bridged into Component
ReactDOM.createRoot(document.getElementById('root')!).render(
<FiberProvider>
<DOMContext.Provider value="Hello from react-dom">
<Canvas>
<Component />
</Canvas>
</DOMContext.Provider>
</FiberProvider>,
)
```
## Utils
Additional exported utility functions for raw handling of Fibers.
### traverseFiber
Traverses up or down a `Fiber`, return `true` to stop and select a node.
```ts
import { type Fiber, traverseFiber } from 'its-fine'
// Traverses through the Fiber tree, returns the current node when `true` is passed via selector
const parentDiv: Fiber<HTMLDivElement> | undefined = traverseFiber<HTMLDivElement>(
// Input Fiber to traverse
fiber as Fiber,
// Whether to ascend and walk up the tree. Will walk down if `false`
true,
// A Fiber node selector, returns the first match when `true` is passed
(node: Fiber<HTMLDivElement | null>) => node.type === 'div',
)
```