Package Exports

@rooks/use-mutation-observer-ref

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@rooks/use-mutation-observer-ref) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

@rooks/use-mutation-observer-ref

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