@apollo/react-hooks

React Apollo - Hooks

React Apollo Hooks.

NOTE: Full React Apollo Hooks usage documentation is coming soon, and when ready will be made available in the main React Apollo documentation. The contents of this README are intended to help beta testers, and will change.

Contents

1. Installation
2. Hooks Overview

• useQuery
• useMutation
• useSubscription
• useApolloClient

1. Reference

Installation

npm install @apollo/react-hooks

Hooks Overview

a) useQuery

Function:

export function useQuery<TData = any, TVariables = OperationVariables>(
  query: DocumentNode,
  options?: QueryHookOptions<TData, TVariables>
): QueryResult<TData, TVariables>;

Options:

query?: DocumentNode;
displayName?: string;
skip?: boolean;
onCompleted?: (data: TData) => void;
onError?: (error: ApolloError) => void;
ssr?: boolean;
variables?: TVariables;
fetchPolicy?: WatchQueryFetchPolicy;
errorPolicy?: ErrorPolicy;
pollInterval?: number;
client?: ApolloClient<any>;
notifyOnNetworkStatusChange?: boolean;
context?: Context;
partialRefetch?: boolean;
returnPartialData?: boolean

Result:

• client: ApolloClient;
• data: TData | undefined;
• error?: ApolloError;
• loading: boolean;
• networkStatus: NetworkStatus;
• fetchMore: any;

Example (from the Hooks demo app):

const GET_ROCKET_INVENTORY = gql`
  query getRocketInventory {
    rocketInventory {
      id
      model
      year
      stock
    }
  }
`;

export function RocketInventoryList() {
  const { loading, data } = useQuery(GET_ROCKET_INVENTORY);
  return (
    <Row className="rocket-inventory-list mt-4">
      <Col sm="12">
        <h3>Available Inventory</h3>
        {loading ? (
          <p>Loading ...</p>
        ) : (
          <table className="table table-striped table-bordered">
            <thead>
              <tr>
                <th>Model</th>
                <th>Year</th>
                <th>Stock</th>
              </tr>
            </thead>
            <tbody>
              {data.rocketInventory.map((inventory: RocketInventory) => (
                <tr
                  key={`${inventory.model}-${inventory.year}-${
                    inventory.stock
                  }`}
                >
                  <td>{inventory.model}</td>
                  <td>{inventory.year}</td>
                  <td>{inventory.stock}</td>
                </tr>
              ))}
            </tbody>
          </table>
        )}
      </Col>
    </Row>
  );
}

b) useMutation

Function:

export function useMutation<TData = any, TVariables = OperationVariables>(
  mutation: DocumentNode,
  options?: MutationHookOptions<TData, TVariables>
): MutationTuple<TData, TVariables>;

Options:

mutation?: DocumentNode;
variables?: TVariables;
optimisticResponse?: TData | ((vars: TVariables) => TData);
refetchQueries?: Array<string | PureQueryOptions> | RefetchQueriesFunction;
awaitRefetchQueries?: boolean;
errorPolicy?: ErrorPolicy;
update?: MutationUpdaterFn<TData>;
client?: ApolloClient<object>;
notifyOnNetworkStatusChange?: boolean;
context?: Context;
onCompleted?: (data: TData) => void;
onError?: (error: ApolloError) => void;
fetchPolicy?: WatchQueryFetchPolicy;
ignoreResults?: boolean;

Result:

[
  (
    options?: MutationFunctionOptions<TData, TVariables>
  ) => Promise<void | ExecutionResult<TData>>,
  {
    data?: TData;
    error?: ApolloError;
    loading: boolean;
    called: boolean;
    client?: ApolloClient<object>
  }
];

Example (from the Hooks demo app):

const SAVE_ROCKET = gql`
  mutation saveRocket($rocket: RocketInput!) {
    saveRocket(rocket: $rocket) {
      model
    }
  }
`;

export function NewRocketForm() {
  const [model, setModel] = useState('');
  const [year, setYear] = useState(0);
  const [stock, setStock] = useState(0);

  const [saveRocket, { error, data }] = useMutation<
    {
      saveRocket: RocketInventory;
    },
    { rocket: NewRocketDetails }
  >(SAVE_ROCKET, {
    variables: { rocket: { model: model, year: +year, stock: +stock } },
    refetchQueries: ['getRocketInventory']
  });

  return (
    <div className="new-rocket-form mt-3">
      <h3>Add a Rocket</h3>
      {error ? <Alert color="danger">Oh no! {error.message}</Alert> : null}
      {data && data.saveRocket ? (
        <Alert color="success">
          Model <strong>{data.saveRocket.model}</strong> added!
        </Alert>
      ) : null}
      <Form style={{ border: '1px solid #ddd', padding: '15px' }}>
        <Row>
          <Col sm="6">
            <FormGroup>
              <Label for="model">Model</Label>
              <Input
                type="text"
                name="model"
                id="model"
                onChange={e => setModel(e.target.value)}
              />
            </FormGroup>
          </Col>
          <Col sm="3">
            <FormGroup>
              <Label for="year">Year</Label>
              <Input
                type="number"
                name="year"
                id="year"
                onChange={e => setYear(+e.target.value)}
              />
            </FormGroup>
          </Col>
          <Col sm="3">
            <FormGroup>
              <Label for="stock">Stock</Label>
              <Input
                type="number"
                name="stock"
                id="stock"
                onChange={e => setStock(+e.target.value)}
              />
            </FormGroup>
          </Col>
        </Row>
        <Row>
          <Col
            sm="12"
            className="text-right"
            onClick={e => {
              e.preventDefault();
              if (model && year && stock) {
                saveRocket();
              }
            }}
          >
            <Button>Add</Button>
          </Col>
        </Row>
      </Form>
    </div>
  );
}

c) useSubscription

Function:

export function useSubscription<TData = any, TVariables = OperationVariables>(
  subscription: DocumentNode,
  options?: SubscriptionHookOptions<TData, TVariables>
);

Options:

subscription?: DocumentNode;
variables?: TVariables;
fetchPolicy?: FetchPolicy;
shouldResubscribe?: boolean | ((options: BaseSubscriptionOptions<TData, TVariables>) => boolean);
client?: ApolloClient<object>;
onSubscriptionData?: (options: OnSubscriptionDataOptions<TData>) => any;
onSubscriptionComplete?: () => void;

Example (from the Hooks demo app):

const LATEST_NEWS = gql`
  subscription getLatestNews {
    latestNews {
      content
    }
  }
`;

export function LatestNews() {
  const { loading, data } = useSubscription<News>(LATEST_NEWS);
  return (
    <Card className="bg-light">
      <CardBody>
        <CardTitle>
          <h5>Latest News</h5>
        </CardTitle>
        <CardText>{loading ? 'Loading...' : data!.latestNews.content}</CardText>
      </CardBody>
    </Card>
  );
}

d) useApolloClient

Function:

export function useApolloClient(): ApolloClient<object>;

Result:

ApolloClient instance stored in the current Context.

Example:

const client = useApolloClient();
consol.log('AC instance stored in the Context', client);

Reference

• Main Apollo Client / React Apollo documentation
• useQuery, useMutation and useSubscription Hooks demo app
• Need help? Join us in the Apollo Spectrum community