`useValuesListener`

The useValuesListener hook registers a listener function with a Store that will be called whenever keyed value data in it changes.

useValuesListener(
  listener: ValuesListener,
  listenerDeps?: DependencyList,
  mutator?: boolean,
  storeOrStoreId?: StoreOrStoreId,
): void

	Type	Description
`listener`	`ValuesListener`	The function that will be called whenever keyed value data in the `Store` 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.
returns	`void`	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 useValues hook).

Unlike the addValuesListener method, which returns a listener Id and requires you to remove it manually, the useValuesListener 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 useValuesListener hook to create a listener that is scoped to a single component. When the component is unmounted, the listener is removed from the Store.

import {Provider, useValuesListener} from 'tinybase/ui-react';
import React from 'react';
import {createRoot} from 'react-dom/client';
import {createStore} from 'tinybase';

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

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

store.setValue('open', false);
// -> 'Values changed'

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

Since

v3.0.0