useRelationshipIds

The useRelationshipIds hook gets an array of the Relationship Ids registered with a Relationships object, and registers a listener so that any changes to that result will cause a re-render.

useRelationshipIds(relationshipsOrRelationshipsId?: RelationshipsOrRelationshipsId): Ids

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 useRelationshipIds 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 Relationship Ids in the Relationships object will cause a re-render. When the component containing this hook is unmounted, the listener will be automatically removed.

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

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

const addRelationshipDefinition = () =>
  relationships.setRelationshipDefinition(
    'petSpecies',
    'pets',
    'species',
    'species',
  );
addRelationshipDefinition();
console.log(app.innerHTML);
// -> '<span>["petSpecies"]</span>'