`useParamValueListener`

The useParamValueListener primitive registers a listener function with a Queries object that will be called whenever a single parameter value for a query changes.

useParamValueListener(
  queryId: MaybeAccessor<IdOrNull>,
  paramId: MaybeAccessor<IdOrNull>,
  listener: ParamValueListener,
  queriesOrQueriesId?: MaybeAccessor<undefined | QueriesOrQueriesId>,
): void

	Type	Description
`queryId`	`MaybeAccessor<IdOrNull>`	The `Id` of the query to listen to, or `null` as a wildcard.
`paramId`	`MaybeAccessor<IdOrNull>`	The `Id` of the parameter to listen to, or `null` as a wildcard.
`listener`	`ParamValueListener`	The function that will be called whenever the parameter value changes.
`queriesOrQueriesId?`	`MaybeAccessor<undefined \| QueriesOrQueriesId>`	The `Queries` object to register the listener with: omit for the default context `Queries` object, provide an `Id` for a named context `Queries` 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 useParamValue primitive).

You can either listen to a single parameter (by specifying the query Id and parameter Id as the method's first two parameters) or changes to any parameter (by providing null wildcards).

Both the queryId and paramId parameters can be wildcarded with null. You can listen to a specific parameter in a specific query, any parameter in any query, for example - or every other combination of wildcards.

Unlike the addParamValueListener method, which returns a listener Id and requires you to remove it manually, the useParamValueListener primitive manages this lifecycle for you: when the component unmounts, the listener on the underlying Queries 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 {useParamValueListener} 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');
  useParamValueListener('petColors', 'species', () => undefined, queries);
  dispose();
});

Since

v8.3.0