`useSubscribeToRecordList`

This Enterprise Edition hook is a specialized version of useSubscribe that subscribes to events concerning a list of records.

Usage

useSubscribeToRecordList expects a callback function as its first argument. It will be executed whenever an event is published on the resource/[resource] topic.

For instance, the following component displays notifications when a record is created, updated, or deleted by someone else:

import React from 'react';
import { useNotify, useListContext } from 'react-admin';
import { useSubscribeToRecordList } from '@react-admin/ra-realtime';

const ListWatcher = () => {
    const notity = useNotify();
    const { refetch, data } = useListContext();
    useSubscribeToRecordList(event => {
        switch (event.type) {
            case 'created': {
                notity('New movie created');
                refetch();
                break;
            }
            case 'updated': {
                if (data.find(record => record.id === event.payload.ids[0])) {
                    notity(`Movie #${event.payload.ids[0]} updated`);
                    refetch();
                }
                break;
            }
            case 'deleted': {
                if (data.find(record => record.id === event.payload.ids[0])) {
                    notity(`Movie #${event.payload.ids[0]} deleted`);
                    refetch();
                }
                break;
            }
        }
    });
    return null;
};

const MovieList = () => (
    <List>
        <Datagrid>
            <TextField source="id" />
            <TextField source="title" />
            <TextField source="director" />
            <TextField source="year" />
        </Datagrid>
        <ListWatcher />
    </List>
);

Parameters

Prop	Required	Type	Default	Description
`callback`	Required	`function`	-	The callback function to execute when an event is published on the topic.
`resource`	Optional	`string`	-	The resource to subscribe to. Defaults to the resource in the `ResourceContext`.
`options`	Optional	`object`	-	The subscription options.

`callback`

Whenever an event is published on the resource/[resource] topic, the function passed as the first argument will be called with the event as a parameter.

const notity = useNotify();
const { refetch, data } = useListContext();
useSubscribeToRecordList(event => {
    switch (event.type) {
        case 'created': {
            notity('New movie created');
            refetch();
            break;
        }
        case 'updated': {
            if (data.find(record => record.id === event.payload.ids[0])) {
                notity(`Movie #${event.payload.ids[0]} updated`);
                refetch();
            }
            break;
        }
        case 'deleted': {
            if (data.find(record => record.id === event.payload.ids[0])) {
                notity(`Movie #${event.payload.ids[0]} deleted`);
                refetch();
            }
            break;
        }
    }
});

Tip: Memoize the callback using useCallback to avoid unnecessary subscriptions/unsubscriptions.

const notity = useNotify();
const { refetch, data } = useListContext();
const callback = useCallback(
    event => {
        switch (event.type) {
            case 'created': {
                notity('New movie created');
                refetch();
                break;
            }
            case 'updated': {
                if (data.find(record => record.id === event.payload.ids[0])) {
                    notity(`Movie #${event.payload.ids[0]} updated`);
                    refetch();
                }
                break;
            }
            case 'deleted': {
                if (data.find(record => record.id === event.payload.ids[0])) {
                    notity(`Movie #${event.payload.ids[0]} deleted`);
                    refetch();
                }
                break;
            }
        }
    },
    [data, refetch, notity]
);
useSubscribeToRecordList(callback);

Just like for useSubscribe, the callback function receives an unsubscribe callback as its second argument. You can call it to unsubscribe from the topic after receiving a specific event.

`options`

The options object can contain the following properties:

enabled: Whether to subscribe or not. Defaults to true
once: Whether to unsubscribe after the first event. Defaults to false.
unsubscribeOnUnmount: Whether to unsubscribe on unmount. Defaults to true.

See useSubscribe for more details.

`resource`

useSubscribeToRecordList reads the current resource from the ResourceContext. You can provide the resource explicitly if you are not in such a context:

useSubscribeToRecordList(event => {
    if (event.type === 'updated') {
        notify('Post updated');
        refresh();
    }
}, 'posts');