`useLinkedRowIdsListener`

The useLinkedRowIdsListener hook registers a listener function with the Relationships object that will be called whenever the linked Row Ids in a Relationship change.

useLinkedRowIdsListener(
  relationshipId: string,
  firstRowId: string,
  listener: LinkedRowIdsListener,
  listenerDeps?: DependencyList,
  relationshipsOrRelationshipsId?: RelationshipsOrRelationshipsId,
): void

	Type	Description
`relationshipId`	`string`	The `Id` of the `Relationship` to listen to.
`firstRowId`	`string`	The `Id` of the first `Row` of the linked list to listen to.
`listener`	`LinkedRowIdsListener`	The function that will be called whenever the linked `Row` `Ids` 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.
`relationshipsOrRelationshipsId?`	`RelationshipsOrRelationshipsId`	The `Relationships` object to register the listener with: omit for the default context `Relationships` object, provide an `Id` for a named context `Relationships` object, 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 useLinkedRowsId hook).

Unlike other listener registration methods, you cannot provide null wildcards for the first two parameters of the useLinkedRowIdsListener method. This prevents the prohibitive expense of tracking all the possible linked lists (and partial linked lists within them) in a Store.

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

Example

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

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

const App = ({relationships}) => (
  <Provider relationships={relationships}>
    <Pane />
  </Provider>
);
const Pane = () => {
  useLinkedRowIdsListener('petSequence', 'fido', () =>
    console.log('Linked Row Ids changed'),
  );
  return <span>App</span>;
};

const store = createStore().setTable('pets', {
  fido: {species: 'dog', next: 'felix'},
  felix: {species: 'cat', next: 'cujo'},
  cujo: {species: 'dog'},
});
const relationships = createRelationships(store);
relationships.setRelationshipDefinition(
  'petSequence',
  'pets',
  'pets',
  'next',
);

const app = document.createElement('div');
const root = createRoot(app);
root.render(<App relationships={relationships} />);
console.log(relationships.getListenerStats().linkedRowIds);
// -> 1

store.setRow('pets', 'toto', {species: 'dog'});
store.setCell('pets', 'cujo', 'next', 'toto');
// -> 'Linked Row Ids changed'

root.unmount();
console.log(relationships.getListenerStats().linkedRowIds);
// -> 0

Since

v1.0.0