`useCheckpointListener`

The useCheckpointListener primitive registers a listener function with the Checkpoints object that will be called whenever the label of a checkpoint changes.

useCheckpointListener(
  checkpointId: MaybeAccessor<IdOrNull>,
  listener: CheckpointListener,
  checkpointsOrCheckpointsId?: MaybeAccessor<undefined | CheckpointsOrCheckpointsId>,
): void

	Type	Description
`checkpointId`	`MaybeAccessor<IdOrNull>`	The `Id` of the checkpoint to listen to, or `null` as a wildcard.
`listener`	`CheckpointListener`	The function that will be called whenever the checkpoint label changes.
`checkpointsOrCheckpointsId?`	`MaybeAccessor<undefined \| CheckpointsOrCheckpointsId>`	The `Checkpoints` object to register the listener with: omit for the default context `Checkpoints` object, provide an `Id` for a named context `Checkpoints` object, or provide an explicit reference.
returns	`void`	This has no return value.

This primitive 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 useCheckpoint primitive).

You can either listen to a single checkpoint label (by specifying the checkpoint Id as the method's first parameter), or changes to any checkpoint label (by providing a null wildcard).

Unlike the addCheckpointListener method, which returns a listener Id and requires you to remove it manually, the useCheckpointListener primitive manages this lifecycle for you: when the component unmounts, the listener on the underlying Checkpoints object will be deleted.

Example

This example creates the TinyBase objects needed by the Solid primitive or component and calls it from within a reactive root.

import {createRoot} from 'solid-js';
import {
  createCheckpoints,
  createIndexes,
  createMetrics,
  createQueries,
  createRelationships,
  createStore,
} from 'tinybase';
import {useCheckpointListener} from 'tinybase/ui-solid';

createRoot((dispose) => {
  const store = createStore()
    .setTables({
      pets: {
        fido: {species: 'dog', color: 'brown', next: 'felix'},
        felix: {species: 'cat', color: 'black'},
      },
      species: {dog: {price: 5}, cat: {price: 4}},
    })
    .setValues({open: true});
  const metrics = createMetrics(store).setMetricDefinition(
    'highestPrice',
    'species',
    'max',
    'price',
  );
  const indexes = createIndexes(store).setIndexDefinition(
    'bySpecies',
    'pets',
    'species',
  );
  const relationships = createRelationships(store)
    .setRelationshipDefinition('petSpecies', 'pets', 'species', 'species')
    .setRelationshipDefinition('nextPet', 'pets', 'pets', 'next');
  const queries = createQueries(store).setQueryDefinition(
    'petColors',
    'pets',
    ({select, where, param}) => {
      select('color');
      where((getCell) => getCell('species') == param('species'));
    },
    {species: 'dog'},
  );
  const checkpoints = createCheckpoints(store);
  store.setCell('pets', 'fido', 'color', 'walnut');
  checkpoints.setCheckpoint('updated color');
  metrics.getMetric('highestPrice');
  indexes.getSliceIds('bySpecies');
  relationships.getRemoteRowId('petSpecies', 'fido');
  queries.getResultRowIds('petColors');
  useCheckpointListener('0', () => undefined, checkpoints);
  dispose();
});

Since

v8.3.0