<ReferenceManyFieldBase>

<ReferenceManyFieldBase> is useful for displaying a list of related records via a one-to-many relationship, when the foreign key is carried by the referenced resource.

This component fetches a list of referenced records by a reverse lookup of the current record.id in the target field of another resource (using the dataProvider.getManyReference() REST method), and puts them in a ListContext.

This component is headless. It relies on its children or a render prop to render the desired ui.

Tip: If the relationship is materialized by an array of ids in the initial record, use the <ReferenceArrayFieldBase> component instead.

Usage

For instance, if an author has many books, and each book resource exposes an author_id field:

┌────────────────┐       ┌──────────────┐
│ authors        │       │ books        │
│----------------│       │--------------│
│ id             │───┐   │ id           │
│ first_name     │   └──╼│ author_id    │
│ last_name      │       │ title        │
│ date_of_birth  │       │ published_at │
└────────────────┘       └──────────────┘

<ReferenceManyFieldBase> can render the titles of all the books by a given author.

import { ShowBase, ReferenceManyFieldBase } from 'ra-core';

const AuthorShow = () => (
    <ShowBase>
        <ReferenceManyFieldBase reference="books" target="author_id" >
            <BookList source="title" />
        </ReferenceManyFieldBase>
    </ShowBase>
);

const BookList = ({
    source,
    children,
}: {
    source: string;
}) => {
    const context = useListContext();

    if (context.isPending) {
        return <p>Loading...</p>;
    }

    if (context.error) {
        return <p className="error">{context.error.toString()}</p>;
    }
    return (
        <p>
            {listContext.data?.map((book, index) => (
                <li key={index}>{book[source]}</li>
            ))}
        </p>
    );
};

<ReferenceManyFieldBase> accepts a reference attribute, which specifies the resource to fetch for the related record. It also accepts a source attribute which defines the field containing the value to look for in the target field of the referenced resource. By default, this is the id of the resource (authors.id in the previous example).

You can also use <ReferenceManyFieldBase> in a list, e.g. to display the authors of the comments related to each post in a list by matching post.id to comment.post_id:

import { ListBase, ListIterator, ReferenceManyFieldBase } from 'ra-core';

export const PostList = () => (
    <ListBase>
        <ListIterator>
            <ReferenceManyFieldBase reference="comments" target="post_id">
                <CustomAuthorView source="name"/>
            </ReferenceManyFieldBase>
        </ListIterator>
    </ListBase>
);

Props

Prop	Required	Type	Default	Description
children	Optional	Element	-	One or several elements that render a list of records based on a ListContext
render	Optional*	(ListContext) => Element	-	Function that receives a ListContext and returns an element
debounce	Optional*	number	500	debounce time in ms for the setFilters callbacks
empty	Optional	ReactNode	-	Element to display when there are no related records.
filter	Optional	Object	-	Filters to use when fetching the related records, passed to getManyReference()
offline	Optional	ReactNode	-	Element to display when there are no related records because of lack of network connectivity.
perPage	Optional	number	25	Maximum number of referenced records to fetch
queryOptions	Optional	UseQuery Options	{}	react-query options for the getMany query
reference	Required	string	-	The name of the resource for the referenced records, e.g. ‘books’
sort	Optional	{ field, order }	{ field: 'id', order: 'DESC' }	Sort order to use when fetching the related records, passed to getManyReference()
source	Optional	string	id	Target field carrying the relationship on the source record (usually ‘id’)
storeKey	Optional	string	-	The key to use to store the records selection state
target	Required	string	-	Target field carrying the relationship on the referenced resource, e.g. ‘user_id’

* Either one of children or render is required.

children

<ReferenceManyFieldBase> renders its children inside a ListContext. This means you can use any list iterator component as child.

For instance, use a <ListIterator> to render the related records:

import { ShowBase, ReferenceManyFieldBase, ListIterator } from 'ra-core';

export const AuthorShow = () => (
    <ShowBase>
        <ReferenceManyFieldBase label="Books" reference="books" target="author_id">
            <ul>
                <ListIterator render={(book) => (
                    <li key={book.id}>
                        <i>{book.title}</i>, published on{' '}{book.published_at}
                    </li>
                )}/>
            </ul>
        </ReferenceManyFieldBase>
    </ShowBase>
);

debounce

By default, <ReferenceManyFieldBase> does not refresh the data as soon as the user enters data in the filter form. Instead, it waits for half a second of user inactivity (via lodash.debounce) before calling the dataProvider on filter change. This is to prevent repeated (and useless) calls to the API.

You can customize the debounce duration in milliseconds - or disable it completely - by passing a debounce prop to the <ReferenceManyFieldBase> component:

// wait 1 seconds instead of 500 milliseconds before calling the dataProvider
const PostCommentsField = () => (
    <ReferenceManyFieldBase debounce={1000}>
        ...
    </ReferenceManyFieldBase>
);

empty

Use empty to customize the text displayed when there are no related records.

<ReferenceManyFieldBase
    reference="books"
    target="author_id"
    empty="no books"
>
    ...
</ReferenceManyFieldBase>

empty also accepts a ReactNode.

<ReferenceManyFieldBase
    reference="books"
    target="author_id"
    empty={<button onClick={...}>Create</button>}
>
    ...
</ReferenceManyFieldBase>

filter: Permanent Filter

You can filter the query used to populate the possible values. Use the filter prop for that.

<ReferenceManyFieldBase
  reference="comments"
  target="post_id"
  filter={{ is_published: true }}
>
   ...
</ReferenceManyFieldBase>

offline

Use offline to customize the text displayed when there are no related records because of lack of network connectivity.

<ReferenceManyFieldBase
    reference="books"
    target="author_id"
    offline="Offline, could not load data"
>
    ...
</ReferenceManyFieldBase>

offline also accepts a ReactNode.

<ReferenceManyFieldBase
    reference="books"
    target="author_id"
    empty={<p>Offline, could not load data</p>}
>
    ...
</ReferenceManyFieldBase>

perPage

By default, ra-core restricts the possible values to 25 and displays no pagination control. You can change the limit by setting the perPage prop:

<ReferenceManyFieldBase perPage={10} reference="comments" target="post_id">
   ...
</ReferenceManyFieldBase>

queryOptions

Use the queryOptions prop to pass options to the dataProvider.getMany() query that fetches the referenced record.

For instance, to pass a custom meta:

<ReferenceManyFieldBase queryOptions={{ meta: { foo: 'bar' } }}>
    ...
</ReferenceManyFieldBase>

reference

The name of the resource to fetch for the related records.

For instance, if you want to display the books of a given author, the reference name should be books:

<ReferenceManyFieldBase label="Books" reference="books" target="author_id">
    ...
</ReferenceManyFieldBase>

render

Alternatively, you can pass a render function prop instead of children. The render prop will receive the ListContext as arguments, allowing to inline the render logic. When receiving a render function prop the <ReferenceManyFieldBase> component will ignore the children property.

import { ShowBase, ReferenceManyFieldBase } from 'react-admin';

const AuthorShow = () => (
    <ShowBase>
        <ReferenceManyFieldBase
            reference="books"
            target="author_id"
            render={
                ({ isPending, error, data }) => {

                    if (isPending) {
                        return <p>Loading...</p>;
                    }

                    if (error) {
                        return <p className="error">{error.toString()}</p>;
                    }
                    return (
                        <ul>
                            {data.map((book, index) => (
                                <li key={index}>
                                    <i>{book.title}</i>, published on{' '}{book.published_at}
                                </li>
                            ))}
                        </ul>
                    );
                }
            }
        />
    </ShowBase>
);

sort

By default, it orders the possible values by id desc. You can change this order by setting the sort prop (an object with field and order properties).

<ReferenceManyFieldBase
    target="post_id"
    reference="comments"
    sort={{ field: 'created_at', order: 'DESC' }}
>
    ...
</ReferenceManyFieldBase>

source

By default, ReferenceManyFieldBase uses the id field as target for the reference. If the foreign key points to another field of your record, you can select it with the source prop.

<ReferenceManyFieldBase
    target="post_id"
    reference="comments"
    source="_id"
>
   ...
</ReferenceManyFieldBase>

storeKey

By default, ra-core stores the reference list selection state in localStorage so that users can come back to the list and find it in the same state as when they left it. Ra-core uses the main resource, record id and reference resource as the identifier to store the selection state (under the key ${resource}.${record.id}.${reference}.selectedIds).

If you want to display multiple lists of the same reference and keep distinct selection states for each one, you must give each list a unique storeKey property.

In the example below, both lists use the same reference (‘books’), but their selection states are stored separately (under the store keys 'authors.1.books.selectedIds' and 'custom.selectedIds' respectively). This allows to use both components in the same page, each having its own state.

<div>
    <ReferenceManyFieldBase
        reference="books"
        target="author_id"
        queryOptions={{
            meta: { foo: 'bar' },
        }}
    >
        <ListIterator render={(book) => (
            <p>{book.title}</p>
        )} />
    </ReferenceManyFieldBase>
    <ReferenceManyFieldBase
        reference="books"
        target="author_id"
        queryOptions={{
            meta: { foo: 'bar' },
        }}
        storeKey="custom"
    >
        <Iterator render={(book) => (
            <p>{book.title}</p>
        )} />
    </ReferenceManyFieldBase>
</div>

target

Name of the field carrying the relationship on the referenced resource. For instance, if an author has many books, and each book resource exposes an author_id field, the target would be author_id.

<ReferenceManyFieldBase label="Books" reference="books" target="author_id">
    ...
</ReferenceManyFieldBase>