useRefetchable

You can use useRefetchable when you want to fetch and re-render a fragment with different data:

Arguments:

They are the same as useFragment.

Return Value:

Object containing the following properties:

• data: Object that contains data which has been read out from the Relay store; the object matches the shape of specified fragment.
• error: Error will be defined if an error has occurred while refetching the query
• isLoading: Boolean value which indicates if a refetch is currently in flight, including any incremental data payloads.
• refetch: Function used to refetch the connection fragment with a potentially new set of variables.
  • Arguments:
    • variables: Object containing the new set of variable values to be used to fetch the @refetchable query.
      • These variables need to match GraphQL variables referenced inside the fragment.
      • However, only the variables that are intended to change for the refetch request need to be specified; any variables referenced by the fragment that are omitted from this input will fall back to using the value specified in the original parent query. So for example, to refetch the fragment with the exact same variables as it was originally fetched, you can call refetch({}).
      • Similarly, passing an id value for the $id variable is optional, unless the fragment wants to be refetched with a different id. When refetching a @refetchable fragment, Relay will already know the id of the rendered object.
    • options: [Optional] options object
      • fetchPolicy: Determines if cached data should be used, and when to send a network request based on cached data that is available. See the useQuery section for full specification.
      • onComplete: Function that will be called whenever the refetch request has completed, including any incremental data payloads.
  • Return value:
    • disposable: Object containing a dispose function. Calling disposable.dispose() will cancel the refetch request.
  • Behavior:
    • Calling refetch with a new set of variables will fetch the fragment again with the newly provided variables. Note that the variables you need to provide are only the ones referenced inside the fragment.
    • Calling refetch will not cause the component to suspend. Instead, the isLoading value will be set to true while the request is in flight

Behavior

• The component is automatically subscribed to updates to the fragment data: if the data for this particular User is updated anywhere in the app (e.g. via fetching new data, or mutating existing data), the component will automatically re-render with the latest updated data.

Differences with RefetchContainer

• A refetch query no longer needs to be specified in this api, since it will be automatically generated by Relay by using a @refetchable fragment.
• Refetching no longer has a distinction between refetchVariables and renderVariables, which were previously vaguely defined concepts. Refetching will always correctly refetch and render the fragment with the variables you provide (any variables omitted in the input will fallback to using the original values from the parent query).
• Refetching will unequivocally update the component, which was not always true when calling refetch from RefetchContainer (it would depend on what you were querying for in the refetch query and if your fragment was defined on the right object type).

import { useRefetchable, graphql } from 'relay-hooks';

const fragmentSpec = graphql`
    fragment TodoList_user on User
    @refetchable(queryName: "TodoListRefetchQuery") {
      todos(
        first: 2147483647 # max GraphQLInt
      ) @connection(key: "TodoList_todos") {
        edges {
          node {
            id
            complete
            ...Todo_todo
          }
        }
      }
      id
      userId
      totalCount
      completedCount
      ...Todo_user
    }
  `;

const options = {
    renderVariables: null,
    observerOrCallback: () => { console.log('Refetch done') },
    refetchOptions: {force: true},
}

const TodoApp = (props) => {
    const { data: user, refetch } = useRefetchable(fragmentSpec, props.user);
    const handlerRefetch = React.useCallback( () => refetch({}), [refetch]);

    return (   
        <div>
            <p> {user.id} </p>
            <p> {user.userId} </p>
            <p> {user.totalCount} </p>
            <button onClick={handlerRefetch}> Refetch </button>
        </div>
        );
};
  

useRefetchableFragment (with suspense, like relay-experimental)

import { useRefetchableFragment } from 'relay-hooks';

See useRefetchableFragment