`useResultCell`

The useResultCell hook returns the value of a single Cell in a given Row in the ResultTable of the given query, and registers a listener so that any changes to that value will cause a re-render.

useResultCell(
  queryId: string,
  rowId: string,
  cellId: string,
  queriesOrQueriesId?: QueriesOrQueriesId,
): Cell | undefined

	Type	Description
`queryId`	`string`	The `Id` of the query.
`rowId`	`string`	The `Id` of the `Row` in the `ResultTable`.
`cellId`	`string`	The `Id` of the `Cell` in the `Row`.
`queriesOrQueriesId?`	`QueriesOrQueriesId`	The `Queries` object to be accessed: omit for the default context `Queries` object, provide an `Id` for a named context `Queries` object, or provide an explicit reference.
returns	`Cell \| undefined`	The value of the `Cell`, or `undefined`.

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

When first rendered, this hook will create a listener so that changes to the result Cell will cause a re-render. When the component containing this hook is unmounted, the listener will be automatically removed.

Examples

This example creates a Queries object outside the application, which is used in the useResultCell hook by reference. A change to the data in the query re-renders the component.

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

const store = createStore().setTable('pets', {
  fido: {species: 'dog', color: 'brown'},
  felix: {species: 'cat', color: 'black'},
  cujo: {species: 'dog', color: 'black'},
});
const queries = createQueries(store).setQueryDefinition(
  'dogColors',
  'pets',
  ({select, where}) => {
    select('species');
    select('color');
    select('legs');
    where('species', 'dog');
  },
);
const App = () => (
  <span>{useResultCell('dogColors', 'fido', 'color', queries)}</span>
);

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

store.setCell('pets', 'fido', 'color', 'walnut');
console.log(app.innerHTML);
// -> '<span>walnut</span>'

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

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

const App = ({queries}) => (
  <Provider queries={queries}>
    <Pane />
  </Provider>
);
const Pane = () => (
  <span>{useResultCell('dogColors', 'fido', 'color')}</span>
);

const queries = createQueries(
  createStore().setTable('pets', {
    fido: {species: 'dog', color: 'brown'},
    felix: {species: 'cat', color: 'black'},
    cujo: {species: 'dog', color: 'black'},
  }),
).setQueryDefinition('dogColors', 'pets', ({select, where}) => {
  select('species');
  select('color');
  where('species', 'dog');
});
const app = document.createElement('div');
createRoot(app).render(<App queries={queries} />);
console.log(app.innerHTML);
// -> '<span>brown</span>'

This example creates a Provider context into which a Queries object is provided, named by Id. A component within it then uses the useResultCell hook.

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

const App = ({queries}) => (
  <Provider queriesById={{petQueries: queries}}>
    <Pane />
  </Provider>
);
const Pane = () => (
  <span>{useResultCell('dogColors', 'fido', 'color', 'petQueries')}</span>
);

const queries = createQueries(
  createStore().setTable('pets', {
    fido: {species: 'dog', color: 'brown'},
    felix: {species: 'cat', color: 'black'},
    cujo: {species: 'dog', color: 'black'},
  }),
).setQueryDefinition('dogColors', 'pets', ({select, where}) => {
  select('species');
  select('color');
  where('species', 'dog');
});
const app = document.createElement('div');
createRoot(app).render(<App queries={queries} />);
console.log(app.innerHTML);
// -> '<span>brown</span>'

Since

v2.0.0