useMetricIds

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

useMetricIds(metricsOrMetricsId?: MetricsOrMetricsId): Ids

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

When first rendered, this hook will create a listener so that changes to the Metric Ids in the Metrics 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 metrics = createMetrics(store);
const App = () => <span>{JSON.stringify(useMetricIds(metrics))}</span>;

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

const addMetricDefinition = () =>
  metrics.setMetricDefinition('highestPrice', 'species', 'max', 'price');
addMetricDefinition();
console.log(app.innerHTML);
// -> '<span>["highestPrice"]</span>'