useMutationObserver

Watch for changes being made to the DOM tree. MutationObserver MDN

Usage

Live Editor

function Demo() {
  const options = { attributes: true };
  const [width, setWidth] = useState(200);
  const [count, setCount] = useState(0);

  const ref = useRef<HTMLDivElement>(null);

  const stop = useMutationObserver(
    (mutationsList) => {
      mutationsList.forEach(() => setCount(c => c + 1));
    },
    ref,
    options,
  );

  useEffect(() => {
    setWidth(300);
  }, []);

  return (
    <div>
      <div
        ref={ref}
        style={{
          width,
          padding: 12,
          border: "1px solid #000",
          marginBottom: 8,
        }}
      >
        current width：{width}
      </div>
      <button onClick={() => setWidth(w => w + 10)}>widening</button>
      <button onClick={() => stop()}>stop observe</button>
      <p>Mutation count {count}</p>
    </div>
  );
};

Result

Loading...

API

UseMutationObserver

Returns

() => void: stop listenering function

Arguments

Argument	Description	Type	DefaultValue
callback	callback	MutationCallback (Required)	-
target	dom对象	BasicTarget (Required)	-
options	options passed to MutationObserver	MutationObserverInit | undefined	-

BasicTarget

export type BasicTarget<T extends TargetType = Element> = (() => TargetValue<T>) | TargetValue<T> | MutableRefObject<TargetValue<T>>;

TargetValue

type TargetValue<T> = T | undefined | null;

TargetType

type TargetType = HTMLElement | Element | Window | Document | EventTarget;