`useLinkedRowIds`

The useLinkedRowIds hook gets the linked Row Ids for a given Row in a linked list Relationship, and registers a listener so that any changes to that result will cause a re-render.

useLinkedRowIds(
  relationshipId: Id,
  firstRowId: Id,
  relationshipsOrRelationshipsId?: any,
): Ids

	Type	Description
`relationshipId`	`Id`	The `Id` of the `Relationship`.
`firstRowId`	`Id`	The `Id` of the first `Row` in the linked list `Relationship`.
`relationshipsOrRelationshipsId?`	`any`	The `Relationships` object to be accessed: omit for the default context `Relationships` object, provide an `Id` for a named context `Relationships` object, or provide an explicit reference.
returns	`Ids`	The linked `Row` `Ids` in the `Relationship`.

A Provider component is used to wrap part of an application in a context, and it can contain a default Relationships object or a set of Relationships objects named by Id. The useLinkedRowIds hook lets you indicate which Relationships object to get data for: omit the optional final parameter for the default context Relationships object, provide an Id for a named context Relationships object, or provide a Relationships object explicitly by reference.

When first rendered, this hook will create a listener so that changes to the linked Row Ids will cause a re-render. When the component containing this hook is unmounted, the listener will be automatically removed.

Examples

This example creates a Relationships object outside the application, which is used in the useLinkedRowIds hook by reference. A change to the linked Row Ids re-renders the component.

const store = createStore().setTable('pets', {
  fido: {species: 'dog', next: 'felix'},
  felix: {species: 'cat', next: 'cujo'},
  cujo: {species: 'dog'},
});
const relationships = createRelationships(store).setRelationshipDefinition(
  'petSequence',
  'pets',
  'pets',
  'next',
);
const App = () => (
  <span>
    {JSON.stringify(useLinkedRowIds('petSequence', 'fido', relationships))}
  </span>
);

const app = document.createElement('div');
ReactDOMClient.createRoot(app).render(<App />);
console.log(app.innerHTML);
// -> '<span>["fido","felix","cujo"]</span>'

store.setRow('pets', 'toto', {species: 'dog'});
store.setCell('pets', 'cujo', 'next', 'toto');
console.log(app.innerHTML);
// -> '<span>["fido","felix","cujo","toto"]</span>'

This example creates a Provider context into which a default Relationships object is provided. A component within it then uses the useLinkedRowIds hook.

const App = ({relationships}) => (
  <Provider relationships={relationships}>
    <Pane />
  </Provider>
);
const Pane = () => (
  <span>{JSON.stringify(useLinkedRowIds('petSequence', 'fido'))}</span>
);

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

const app = document.createElement('div');
const root = ReactDOMClient.createRoot(app);
root.render(<App relationships={relationships} />);
console.log(app.innerHTML);
// -> '<span>["fido","felix","cujo"]</span>'

This example creates a Provider context into which a default Relationships object is provided. A component within it then uses the useLinkedRowIds hook.

const App = ({relationships}) => (
  <Provider relationshipsById={{petRelationships: relationships}}>
    <Pane />
  </Provider>
);
const Pane = () => (
  <span>
    {JSON.stringify(
      useLinkedRowIds('petSequence', 'fido', 'petRelationships'),
    )}
  </span>
);

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

const app = document.createElement('div');
const root = ReactDOMClient.createRoot(app);
root.render(<App relationships={relationships} />);
console.log(app.innerHTML);
// -> '<span>["fido","felix","cujo"]</span>'