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@rooks/use-mutation-observer-ref

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Readme

@rooks/use-mutation-observer-ref

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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

import useMutationObserverRef from "@rooks/use-mutation-observer-ref"

Usage

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