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useValueIdsListener

The useValueIdsListener hook registers a listener function with a Store that will be called whenever the Value Ids in it change.

useValueIdsListener(
  listener: ValueIdsListener,
  listenerDeps?: DependencyList,
  mutator?: boolean,
  storeOrStoreId?: any,
): void
TypeDescription
listenerValueIdsListener

The function that will be called whenever the Value Ids in the Store change.

listenerDeps?DependencyList

An optional array of dependencies for the listener function, which, if any change, result in the re-registration of the listener. This parameter defaults to an empty array.

mutator?boolean

An optional boolean that indicates that the listener mutates Store data.

storeOrStoreId?any

The Store to register the listener with: omit for the default context Store, provide an Id for a named context Store, or provide an explicit reference.

returnsvoid

This has no return value.

This hook is useful for situations where a component needs to register its own specific listener to do more than simply tracking the value (which is more easily done with the useValueIds hook).

Unlike the addValueIdsListener method, which returns a listener Id and requires you to remove it manually, the useValueIdsListener hook manages this lifecycle for you: when the listener changes (per its listenerDeps dependencies) or the component unmounts, the listener on the underlying Store will be deleted.

Example

This example uses the useValueIdsListener hook to create a listener that is scoped to a single component. When the component is unmounted, the listener is removed from the Store.

const App = ({store}) => (
  <Provider store={store}>
    <Pane />
  </Provider>
);
const Pane = () => {
  useValueIdsListener(() => console.log('Value Ids changed'));
  return <span>App</span>;
};

const store = createStore().setValues({open: true});
const app = document.createElement('div');
const root = ReactDOMClient.createRoot(app);
root.render(<App store={store} />);
console.log(store.getListenerStats().valueIds);
// -> 1

store.setValue('employees', 3);
// -> 'Value Ids changed'

root.unmount();
console.log(store.getListenerStats().valueIds);
// -> 0

Since

v3.0.0