useListContext
Whenever react-admin displays a List, it creates a ListContext
to store the list data, as well as filters, pagination, sort state, and callbacks to update them.
The ListContext
is available to descendants of:
<List>
,<ListGuesser>
,<ListBase>
,<ReferenceArrayField>
,<ReferenceManyField>
All descendant components can therefore access the list context, using the useListContext
hook. As a matter of fact, react-admin’s <Datagrid>
, <FilterForm>
, and <Pagination>
components all use the useListContext
hook.
Usage
Call useListContext
in a component, then use this component as a descendant of a List
component.
// 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>
);
Return Value
useListContext
returns an object with the following keys:
const {
// Data
data, // Array of the list records, e.g. [{ id: 123, title: 'hello world' }, { ... }
total, // Total number of results for the current filters, excluding pagination. Useful to build the pagination controls, e.g. 23
isFetching, // Boolean, true while the data is being fetched, false once the data is fetched
isLoading, // Boolean, true until the data is available for the first time
// Pagination
page, // Current page. Starts at 1
perPage, // Number of results per page. Defaults to 25
setPage, // Callback to change the page, e.g. setPage(3)
setPerPage, // 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, // Sort object { field, order }, e.g. { field: 'date', order: 'DESC' }
setSort, // Callback to change the sort, e.g. setSort({ field: 'name', order: 'ASC' })
// Filtering
filterValues, // Dictionary of filter values, e.g. { title: 'lorem', nationality: 'fr' }
displayedFilters, // Dictionary of displayed filters, e.g. { title: true, nationality: true }
setFilters, // Callback to update the filters, e.g. setFilters(filters, displayedFilters)
showFilter, // Callback to show one of the filters, e.g. showFilter('title', defaultValue)
hideFilter, // Callback to hide one of the filters, e.g. hideFilter('title')
// Record selection
selectedIds, // Array listing the ids of the selected records, e.g. [123, 456]
onSelect, // Callback to change the list of selected records, e.g. onSelect([456, 789])
onToggleItem, // Callback to toggle the record selection for a given id, e.g. onToggleItem(456)
onUnselectItems, // Callback to clear the record selection, e.g. onUnselectItems();
// Misc
defaultTitle, // Translated title based on the resource, e.g. 'Posts'
resource, // Resource name, deduced from the location. e.g. 'posts'
refetch, // Callback for fetching the list data again
} = useListContext();
Declarative Version
useListContext
often forces you to create a new component just to access the list context. If you prefer a declarative approach based on render props, you can use the <WithListContext>
component instead:
import { WithListContext } from 'react-admin';
import { Typography } from '@mui/material';
export const Aside = () => (
<WithListContext render={({ data, isLoading }) =>
!isLoading && (
<div>
<Typography variant="h6">Posts stats</Typography>
<Typography variant="body2">
Total views: {data.reduce((sum, post) => sum + post.views, 0)}
</Typography>
</div>
)} />
);
Using setFilters
to Update Filters
The setFilters
method is used to update the filters. It takes three arguments:
filters
: an object containing the new filter valuesdisplayedFilters
: an object containing the new displayed filtersdebounced
: set to false to disable the debounce (true by default)
You can use it to update the filters in a custom filter component:
import { useState } from 'react';
import { useListContext } from 'react-admin';
const CustomFilter = () => {
const { filterValues, setFilters } = useListContext();
const [formValues, setFormValues] = useState(filterValues);
const handleChange = (event) => {
setFormValues(formValues => ({
...formValues,
[event.target.name]: event.target.value
}));
};
const handleSubmit = (event) => {
event.preventDefault();
// The 3rd parameter disables the debounce ⤵
setFilters(filterFormValues, undefined, false);
};
return (
<form onSubmit={handleSubmit}>
<input name="country" value={formValues.country} onChange={handleChange} />
<input name="city" value={formValues.city} onChange={handleChange} />
<input name="zipcode" value={formValues.zipcode} onChange={handleChange} />
<input type="submit">Filter</input>
</form>
);
};
Beware that setFilters
is debounced by default, to avoid making too many requests to the server when using search-as-you-type inputs. In the example above, this is not necessary. That’s why you should set the third argument to setFilters
is set to false
to disable the debounce.
Disabling the debounce with the third parameter is also necessary when you use setFilters
and other list context methods (like setSort
) in a single function. Otherwise, the setFilters
call would override the other changes.
const changeListParams = () => {
setSort({ field: 'name', order: 'ASC' });
// The 3rd parameter disables the debounce ⤵
setFilters({ is_published: true }, undefined, false);
};
TypeScript
The useListContext
hook accepts a generic parameter for the record type:
import { Typography } from '@mui/material';
import { List, Datagrid, TextField, useListContext } from 'react-admin';
type Post = {
id: number;
title: string;
views: number;
};
export const Aside = () => {
const { data: posts, isLoading } = useListContext<Post>();
if (isLoading) return null;
return (
<div>
<Typography variant="h6">Posts stats</Typography>
<Typography variant="body2">
{/* TypeScript knows that posts is of type Post[] */}
Total views: {posts.reduce((sum, post) => sum + post.views, 0)}
</Typography>
</div>
);
};
export const PostList = () => (
<List aside={<Aside />}>
<Datagrid>
<TextField source="id" />
<TextField source="title" />
<TextField source="views" />
</Datagrid>
</List>
);
Recipes
You can find many usage examples of useListContext
in the documentation, including:
- Adding a Side Component with
<List actions>
- Building a Custom Actions Bar via
<List actions>
- Building a Custom Empty Page via
<List empty>
- Building a Custom Filter
- Building a Custom Sort Control
- Building a Custom Pagination Control
- Building a Custom Iterator
Tip: <ReferenceManyField>
, as well as other relationship-related components, also implement a ListContext
. That means you can use a <Datagrid>
of a <Pagination>
inside these components!