useListContext

// in src/posts/Aside.js
import { Typography } from '@mui/material';
import { useListContext } from 'react-admin';

export const Aside = () => {
    const { data, isLoading } = useListContext();
    if (isLoading) return null;
    return (
        <div>
            <Typography variant="h6">Posts stats</Typography>
            <Typography variant="body2">
                Total views: {data.reduce((sum, post) => sum + post.views, 0)}
            </Typography>
        </div>
    );
};

// in src/posts/PostList.js
import { List, Datagrid, TextField } from 'react-admin';
import Aside from './Aside';

export const PostList = () => (
    <List aside={<Aside />}>
        <Datagrid>
            <TextField source="id" />
            <TextField source="title" />
            <TextField source="views" />
        </Datagrid>
    </List>
);

const {
    // fetched data
    data, // an array of the list records, e.g. [{ id: 123, title: 'hello world' }, { ... }]
    total, // the total number of results for the current filters, excluding pagination. Useful to build the pagination controls, e.g. 23      
    isFetching, // boolean that is true while the data is being fetched, and false once the data is fetched
    isLoading, // boolean that is true until the data is available for the first time
    // pagination
    page, // the current page. Starts at 1
    perPage, // the number of results per page. Defaults to 25
    setPage, // a callback to change the page, e.g. setPage(3)
    setPerPage, // a callback to change the number of results per page, e.g. setPerPage(25)
    hasPreviousPage, // boolean, true if the current page is not the first one
    hasNextPage, // boolean, true if the current page is not the last one
    // sorting
    sort, // a sort object { field, order }, e.g. { field: 'date', order: 'DESC' }
    setSort, // a callback to change the sort, e.g. setSort({ field: 'name', order: 'ASC' })
    // filtering
    filterValues, // a dictionary of filter values, e.g. { title: 'lorem', nationality: 'fr' }
    displayedFilters, // a dictionary of the displayed filters, e.g. { title: true, nationality: true }
    setFilters, // a callback to update the filters, e.g. setFilters(filters, displayedFilters)
    showFilter, // a callback to show one of the filters, e.g. showFilter('title', defaultValue)
    hideFilter, // a callback to hide one of the filters, e.g. hideFilter('title')
    // record selection
    selectedIds, // an array listing the ids of the selected rows, e.g. [123, 456]
    onSelect, // callback to change the list of selected rows, e.g. onSelect([456, 789])
    onToggleItem, // callback to toggle the selection of a given record based on its id, e.g. onToggleItem(456)
    onUnselectItems, // callback to clear the selection, e.g. onUnselectItems();
    // misc
    defaultTitle, // the translated title based on the resource, e.g. 'Posts'
    resource, // the resource name, deduced from the location. e.g. 'posts'
    refetch, // callback for fetching the list data again
} = useListContext();