TinyBase

useRowListener

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

useRowListener(
  tableId: IdOrNull,
  rowId: IdOrNull,
  listener: RowListener,
  listenerDeps?: DependencyList,
  mutator?: boolean,
  storeOrStoreId?: StoreOrStoreId,
): 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.

listenerRowListener

The function that will be called whenever data in the Row 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?StoreOrStoreId

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 useRow hook).

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

Both, either, or neither of the tableId and rowId parameters can be wildcarded with null. You can listen to a specific Row in a specific Table, any Row in a specific Table, a specific Row in any Table, or any Row in any Table.

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

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

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

ReactDOM.unmountComponentAtNode(app);
console.log(store.getListenerStats().row);
// -> 0