@rooks/use-mutation-observer-ref
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A hook that tracks mutations of an element. It returns a callbackRef.
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# @rooks/use-mutation-observer-ref
## *Note: Future updates to this package have moved to the main package* [rooks](https://npmjs.com/package/rooks). All hooks now reside in a single package which you can install using
```
npm install rooks
```
or
```
yarn add rooks
```
Rooks is completely treeshakeable and if you use only 1 of the 50+ hooks in the package, only that hook will be bundled with your code. Your bundle will only contain the hooks that you need. Cheers!
    
## About
A hook that tracks mutations of an element. It returns a callbackRef.
## Installation
```
npm install --save @rooks/use-mutation-observer-ref
```
## Importing the hook
```javascript
import useMutationObserverRef from "@rooks/use-mutation-observer-ref"
```
## Usage
```jsx
function Demo() {
const [mutationCount, setMutationCount] = useState(0);
const incrementMutationCount = () => {
return setMutationCount(mutationCount + 1);
};
const [myRef] = useMutationObserver(myRef, incrementMutationCount);
const [XOffset, setXOffset] = useState(0);
const [YOffset, setYOffset] = useState(300);
return (
<>
<div
style={{
width: 300,
background: "lightblue",
padding: "10px",
position: "absolute",
left: XOffset,
top: YOffset
}}
ref={myRef}
>
<div
style={{
resize: "both",
overflow: "auto",
background: "white",
color: "blue",
maxWidth: "100%"
}}
>
<p>
Resize this div as you see fit. To demonstrate that it also updates
on child dom nodes resize
</p>
</div>
<h2>Bounds</h2>
<p>
<button onClick={() => setXOffset(XOffset - 5)}> Move Left </button>
<button onClick={() => setXOffset(XOffset + 5)}> Move Right </button>
</p>
<p>
<button onClick={() => setYOffset(YOffset - 5)}> Move Up </button>
<button onClick={() => setYOffset(YOffset + 5)}> Move Down </button>
</p>
</div>
<div style={{ height: 500 }} onClick={incrementMutationCount}>
<pre>Mutation count {mutationCount}</pre>
</div>
</>
);
}
render(<Demo/>)
```
### Arguments
| Argument | Type | Description | Default value |
| -------- | -------- | ------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------- |
| callback | function | Function which should be invoked on mutation. It is called with the `mutationList` and `observer` | undefined |
| config | object | Mutation Observer configuration | {attributes: true,,characterData: true,,subtree: true,,childList: true} |
### Return value
Returns an array with one element
| Argument | Type | Description |
| -------- | --------- | ------------------------------------------ |
| ref | React ref | Ref which should be observed for Mutations |