`useLocalRowIds`

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

useLocalRowIds(
  relationshipId: string,
  remoteRowId: string,
  relationshipsOrRelationshipsId?: RelationshipsOrRelationshipsId,
): Ids

	Type	Description
`relationshipId`	`string`	The `Id` of the `Relationship`.
`remoteRowId`	`string`	The `Id` of the remote `Row` in the `Relationship`.
`relationshipsOrRelationshipsId?`	`RelationshipsOrRelationshipsId`	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 local `Row` `Ids` in the `Relationship`, or an empty array.

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 useLocalRowIds 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 local Row Id 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 useLocalRowIds hook by reference. A change to the local Row Ids re-renders the component.

import {createRelationships, createStore} from 'tinybase';
import React from 'react';
import {createRoot} from 'react-dom/client';
import {useLocalRowIds} from 'tinybase/ui-react';

const store = createStore()
  .setTable('pets', {fido: {species: 'dog'}, cujo: {species: 'dog'}})
  .setTable('species', {wolf: {price: 10}, dog: {price: 5}});
const relationships = createRelationships(store).setRelationshipDefinition(
  'petSpecies',
  'pets',
  'species',
  'species',
);
const App = () => (
  <span>
    {JSON.stringify(useLocalRowIds('petSpecies', 'dog', relationships))}
  </span>
);

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

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

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

import {Provider, useLocalRowIds} from 'tinybase/ui-react';
import {createRelationships, createStore} from 'tinybase';
import React from 'react';
import {createRoot} from 'react-dom/client';

const App = ({relationships}) => (
  <Provider relationships={relationships}>
    <Pane />
  </Provider>
);
const Pane = () => (
  <span>{JSON.stringify(useLocalRowIds('petSpecies', 'dog'))}</span>
);

const relationships = createRelationships(
  createStore()
    .setTable('pets', {fido: {species: 'dog'}, cujo: {species: 'dog'}})
    .setTable('species', {wolf: {price: 10}, dog: {price: 5}}),
).setRelationshipDefinition('petSpecies', 'pets', 'species', 'species');

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

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

import {Provider, useLocalRowIds} from 'tinybase/ui-react';
import {createRelationships, createStore} from 'tinybase';
import React from 'react';
import {createRoot} from 'react-dom/client';

const App = ({relationships}) => (
  <Provider relationshipsById={{petRelationships: relationships}}>
    <Pane />
  </Provider>
);
const Pane = () => (
  <span>
    {JSON.stringify(
      useLocalRowIds('petSpecies', 'dog', 'petRelationships'),
    )}
  </span>
);

const relationships = createRelationships(
  createStore()
    .setTable('pets', {fido: {species: 'dog'}, cujo: {species: 'dog'}})
    .setTable('species', {wolf: {price: 10}, dog: {price: 5}}),
).setRelationshipDefinition('petSpecies', 'pets', 'species', 'species');

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

Since

v1.0.0