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useCellListener

The useCellListener hook registers a listener function with a Store that will be called whenever data in a Cell changes.

useCellListener(
  tableId: IdOrNull,
  rowId: IdOrNull,
  cellId: IdOrNull,
  listener: CellListener,
  listenerDeps?: DependencyList,
  mutator?: boolean,
  storeOrStoreId?: any,
): void
TypeDescription
tableIdIdOrNull

The Id of the Table to listen to, or null as a wildcard.

rowIdIdOrNull

The Id of the Row to listen to, or null as a wildcard.

cellIdIdOrNull

The Id of the Cell to listen to, or null as a wildcard.

listenerCellListener

The function that will be called whenever data in the Cell changes.

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 useCell hook).

You can either listen to a single Cell (by specifying the Table Id, Row Id, and Cell Id as the method's first three parameters) or changes to any Cell (by providing null wildcards).

All, some, or none of the tableId, rowId, and cellId parameters can be wildcarded with null. You can listen to a specific Cell in a specific Row in a specific Table, any Cell in any Row in any Table, for example - or every other combination of wildcards.

Unlike the addCellListener method, which returns a listener Id and requires you to remove it manually, the useCellListener 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 useCellListener 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 = () => {
  useCellListener('pets', 'fido', 'color', () =>
    console.log('Cell changed'),
  );
  return <span>App</span>;
};

const store = createStore().setTables({pets: {fido: {color: 'brown'}}});
const app = document.createElement('div');
const root = ReactDOMClient.createRoot(app);
root.render(<App store={store} />);
console.log(store.getListenerStats().cell);
// -> 1

store.setCell('pets', 'fido', 'color', 'walnut');
// -> 'Cell changed'

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