Hooks

Installation

Apollo Client >= 3 includes React hooks functionality out of the box. You don't need to install any additional packages.

The `ApolloProvider` component

The ApolloProvider component leverages React's Context API to make a configured Apollo Client instance available throughout a React component tree. This component can be imported directly from the @apollo/client package.

import { ApolloProvider } from '@apollo/client';

Props

Option	Type	Description
`client`	ApolloClient<TCache>	An `ApolloClient` instance.

Example

const client = new ApolloClient({
  cache: new InMemoryCache(),
  uri: "http://localhost:4000/graphql"
});

ReactDOM.render(
  <ApolloProvider client={client}>    <MyRootComponent />  </ApolloProvider>,  document.getElementById('root'),
);

The `ApolloConsumer` component

One way to access the configured Apollo Client instance directly is to create an ApolloConsumer component and provide a render prop function as its child. The render prop function will be called with your ApolloClient instance as its only argument. You can think of the ApolloConsumer component as similar to the Consumer component from the React Context API.

Example

import React from 'react';
import { ApolloConsumer } from '@apollo/client';

const WithApolloClient = () => (
  <ApolloConsumer>
    {client => 'We have access to the client!' /* do stuff here */}
  </ApolloConsumer>
);

`useQuery`

Example

import { gql, useQuery } from '@apollo/client';

const GET_GREETING = gql`
  query GetGreeting($language: String!) {
    greeting(language: $language) {
      message
    }
  }
`;

function Hello() {
  const { loading, error, data } = useQuery(GET_GREETING, {
    variables: { language: 'english' },
  });
  if (loading) return <p>Loading ...</p>;
  return <h1>Hello {data.greeting.message}!</h1>;
}

Refer to the Queries section for a more in-depth overview of useQuery.

Function Signature

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

Params

`query`

Param	Type	Description
`query`	DocumentNode	A GraphQL query document parsed into an AST by `gql`.

`options`

Name /
Type Description

Name / Type	Description
Operation options
`query` `DocumentNode`	A GraphQL query string parsed into an AST with the `gql` template literal. Optional for the `useQuery` hook, because the query can be provided as the first parameter to the hook. Required for the `Query` component.
`variables` `{ [key: string]: any }`	An object containing all of the GraphQL variables your query requires to execute. Each key in the object corresponds to a variable name, and that key's value corresponds to the variable value.
`errorPolicy` `ErrorPolicy`	Specifies how the query handles a response that returns both GraphQL errors and partial results. For details, see GraphQL error policies. The default value is `none`, meaning that the query result includes error details but not partial results.
`onCompleted` `(data: TData \| {}) => void`	A callback function that's called when your query successfully completes with zero errors (or if `errorPolicy` is `ignore` and partial data is returned). This function is passed the query's result `data`.
`onError` `(error: ApolloError) => void`	A callback function that's called when the query encounters one or more errors (unless `errorPolicy` is `ignore`). This function is passed an `ApolloError` object that contains either a `networkError` object or a `graphQLErrors` array, depending on the error(s) that occurred.
`skip` `boolean`	If `true`, the query is not executed. Not available with `useLazyQuery`. This property is part of Apollo Client's React integration, and it is not available in the core `ApolloClient` API. The default value is `false`.
`displayName` `string`	The name of your component to be displayed in the React Developer Tools. The default value is `Query`.
Networking options
`pollInterval` `number`	Specifies the interval (in milliseconds) at which the query polls for updated results. The default value is `0` (no polling).
`notifyOnNetworkStatusChange` `boolean`	If `true`, the in-progress query's associated component re-renders whenever the network status changes or a network error occurs. The default value is `false`.
`context` `Record<string, any>`	If you're using Apollo Link, this object is the initial value of the `context` object that's passed along your link chain.
`ssr` `boolean`	Pass `false` to skip executing the query during server-side rendering.
`client` `ApolloClient`	The instance of `ApolloClient` to use to execute the query. By default, the instance that's passed down via context is used, but you can provide a different instance here.
Caching options
`fetchPolicy` `FetchPolicy`	Specifies how the query interacts with the Apollo Client cache during execution (for example, whether it checks the cache for results before sending a request to the server). For details, see Setting a fetch policy. The default value is `cache-first`.
`nextFetchPolicy` `FetchPolicy`	Specifies the `fetchPolicy` to use for all executions of this query after this execution. For example, you can use this to switch back to a `cache-first` fetch policy after using `cache-and-network` or `network-only` for a single execution.
`returnPartialData` `boolean`	If `true`, the query can return partial results from the cache if the cache doesn't contain results for all queried fields. The default value is `false`.
Deprecated options
`partialRefetch` `boolean`	Deprecated. If `true`, causes a query `refetch` if the query result is detected as partial. Setting this option is unnecessary in Apollo Client 3, thanks to a more consistent application of fetch policies. It might be removed in a future release. The default value is `false`.

Operation options

`query`

DocumentNode

A GraphQL query string parsed into an AST with the gql template literal.

Optional for the useQuery hook, because the query can be provided as the first parameter to the hook. Required for the Query component.

`variables`

{ [key: string]: any }

An object containing all of the GraphQL variables your query requires to execute.

Each key in the object corresponds to a variable name, and that key's value corresponds to the variable value.

`errorPolicy`

ErrorPolicy

Specifies how the query handles a response that returns both GraphQL errors and partial results.

For details, see GraphQL error policies.

The default value is none, meaning that the query result includes error details but not partial results.

`onCompleted`

(data: TData | {}) => void

A callback function that's called when your query successfully completes with zero errors (or if errorPolicy is ignore and partial data is returned).

This function is passed the query's result data.

`onError`

(error: ApolloError) => void

A callback function that's called when the query encounters one or more errors (unless errorPolicy is ignore).

This function is passed an ApolloError object that contains either a networkError object or a graphQLErrors array, depending on the error(s) that occurred.

`skip`

boolean

If true, the query is not executed. Not available with useLazyQuery.

This property is part of Apollo Client's React integration, and it is not available in the core ApolloClient API.

The default value is false.

`displayName`

string

The name of your component to be displayed in the React Developer Tools.

The default value is Query.

Networking options

`pollInterval`

number

Specifies the interval (in milliseconds) at which the query polls for updated results.

The default value is 0 (no polling).

`notifyOnNetworkStatusChange`

boolean

If true, the in-progress query's associated component re-renders whenever the network status changes or a network error occurs.

The default value is false.

`context`

Record<string, any>

If you're using Apollo Link, this object is the initial value of the context object that's passed along your link chain.

`ssr`

boolean

Pass false to skip executing the query during server-side rendering.

`client`

ApolloClient

The instance of ApolloClient to use to execute the query.

By default, the instance that's passed down via context is used, but you can provide a different instance here.

Caching options

`fetchPolicy`

FetchPolicy

Specifies how the query interacts with the Apollo Client cache during execution (for example, whether it checks the cache for results before sending a request to the server).

For details, see Setting a fetch policy.

The default value is cache-first.

`nextFetchPolicy`

FetchPolicy

Specifies the fetchPolicy to use for all executions of this query after this execution.

For example, you can use this to switch back to a cache-first fetch policy after using cache-and-network or network-only for a single execution.

`returnPartialData`

boolean

If true, the query can return partial results from the cache if the cache doesn't contain results for all queried fields.

The default value is false.

Deprecated options

`partialRefetch`

boolean

Deprecated. If true, causes a query refetch if the query result is detected as partial. Setting this option is unnecessary in Apollo Client 3, thanks to a more consistent application of fetch policies. It might be removed in a future release.

The default value is false.

Result

Name /
Type Description

Name / Type	Description
Operation data
`data` `TData`	An object containing the result of your GraphQL query after it completes. This value might be `undefined` if a query results in one or more errors (depending on the query's `errorPolicy`).
`previousData` `TData`	An object containing the result from the most recent previous execution of this query. This value is `undefined` if this is the query's first execution.
`error` `ApolloError`	If the query produces one or more errors, this object contains either an array of `graphQLErrors` or a single `networkError`. Otherwise, this value is `undefined`. For more information, see Handling operation errors.
`variables` `{ [key: string]: any }`	An object containing the variables that were provided for the query.
Network info
`loading` `boolean`	If `true`, the query is still in flight and results have not yet been returned.
`networkStatus` `NetworkStatus`	A number indicating the current network state of the query's associated request. See possible values. Used in conjunction with the `notifyOnNetworkStatusChange` option.
`client` `ApolloClient`	The instance of Apollo Client that executed the query. Can be useful for manually executing followup queries or writing data to the cache.
`called` `boolean`	If `true`, the associated lazy query has been executed. This field is only present on the result object returned by `useLazyQuery`.
Helper functions
`refetch` `(variables?: Partial<TVariables>) => Promise<ApolloQueryResult>`	A function that enables you to re-execute the query, optionally passing in new `variables`. The followup execution's `fetchPolicy` is set to `network-only` if the original query's `fetchPolicy` isn't guaranteed to send a network request (such as with `cache-first`). See also Refetching.
`fetchMore` `({ query?: DocumentNode, variables?: TVariables, updateQuery: Function}) => Promise<ApolloQueryResult>`	A function that helps you fetch the next set of results for a paginated list field.
`startPolling` `(interval: number) => void`	A function that instructs the query to begin re-executing at a specified interval (in milliseconds).
`stopPolling` `() => void`	A function that instructs the query to stop polling after a previous call to `startPolling`.
`subscribeToMore` `(options: { document: DocumentNode, variables?: TVariables, updateQuery?: Function, onError?: Function}) => () => void`	A function that enables you to execute a subscription, usually to subscribe to specific fields that were included in the query. This function returns another function that you can call to terminate the subscription.
`updateQuery` `(previousResult: TData, options: { variables: TVariables }) => TData`	A function that enables you to update the query's cached result without executing a followup GraphQL operation.

Operation data

`data`

TData

An object containing the result of your GraphQL query after it completes.

This value might be undefined if a query results in one or more errors (depending on the query's errorPolicy).

`previousData`

TData

An object containing the result from the most recent previous execution of this query.

This value is undefined if this is the query's first execution.

`error`

ApolloError

If the query produces one or more errors, this object contains either an array of graphQLErrors or a single networkError. Otherwise, this value is undefined.

For more information, see Handling operation errors.

`variables`

{ [key: string]: any }

An object containing the variables that were provided for the query.

Network info

`loading`

boolean

If true, the query is still in flight and results have not yet been returned.

`networkStatus`

NetworkStatus

A number indicating the current network state of the query's associated request. See possible values.

Used in conjunction with the notifyOnNetworkStatusChange option.

`client`

ApolloClient

The instance of Apollo Client that executed the query.

Can be useful for manually executing followup queries or writing data to the cache.

`called`

boolean

If true, the associated lazy query has been executed.

This field is only present on the result object returned by useLazyQuery.

Helper functions

`refetch`

(variables?: Partial<TVariables>) => Promise<ApolloQueryResult>

A function that enables you to re-execute the query, optionally passing in new variables.

The followup execution's fetchPolicy is set to network-only if the original query's fetchPolicy isn't guaranteed to send a network request (such as with cache-first).

`fetchMore`

({ query?: DocumentNode, variables?: TVariables, updateQuery: Function}) => Promise<ApolloQueryResult>

A function that helps you fetch the next set of results for a paginated list field.

`startPolling`

(interval: number) => void

A function that instructs the query to begin re-executing at a specified interval (in milliseconds).

`stopPolling`

() => void

A function that instructs the query to stop polling after a previous call to startPolling.

`subscribeToMore`

(options: { document: DocumentNode, variables?: TVariables, updateQuery?: Function, onError?: Function}) => () => void

A function that enables you to execute a subscription, usually to subscribe to specific fields that were included in the query.

This function returns another function that you can call to terminate the subscription.

`updateQuery`

(previousResult: TData, options: { variables: TVariables }) => TData

A function that enables you to update the query's cached result without executing a followup GraphQL operation.

`useLazyQuery`

Example

import { gql, useLazyQuery } from "@apollo/client";

const GET_GREETING = gql`
  query GetGreeting($language: String!) {
    greeting(language: $language) {
      message
    }
  }
`;

function Hello() {
  const [loadGreeting, { called, loading, data }] = useLazyQuery(
    GET_GREETING,
    { variables: { language: "english" } }
  );
  if (called && loading) return <p>Loading ...</p>
  if (!called) {
    return <button onClick={() => loadGreeting()}>Load greeting</button>
  }
  return <h1>Hello {data.greeting.message}!</h1>;
}

Refer to the Queries section for a more in-depth overview of useLazyQuery.

Function Signature

function useLazyQuery<TData = any, TVariables = OperationVariables>(
  query: DocumentNode,
  options?: LazyQueryHookOptions<TData, TVariables>,
): [
  (options?: QueryLazyOptions<TVariables>) => void,
  QueryResult<TData, TVariables>
] {}

Params

`query`

Param	Type	Description
`query`	DocumentNode	A GraphQL query document parsed into an AST by `gql`.

`options`

Name /
Type Description

Name / Type	Description
Operation options
`query` `DocumentNode`	A GraphQL query string parsed into an AST with the `gql` template literal. Optional for the `useQuery` hook, because the query can be provided as the first parameter to the hook. Required for the `Query` component.
`variables` `{ [key: string]: any }`	An object containing all of the GraphQL variables your query requires to execute. Each key in the object corresponds to a variable name, and that key's value corresponds to the variable value.
`errorPolicy` `ErrorPolicy`	Specifies how the query handles a response that returns both GraphQL errors and partial results. For details, see GraphQL error policies. The default value is `none`, meaning that the query result includes error details but not partial results.
`onCompleted` `(data: TData \| {}) => void`	A callback function that's called when your query successfully completes with zero errors (or if `errorPolicy` is `ignore` and partial data is returned). This function is passed the query's result `data`.
`onError` `(error: ApolloError) => void`	A callback function that's called when the query encounters one or more errors (unless `errorPolicy` is `ignore`). This function is passed an `ApolloError` object that contains either a `networkError` object or a `graphQLErrors` array, depending on the error(s) that occurred.
`skip` `boolean`	If `true`, the query is not executed. Not available with `useLazyQuery`. This property is part of Apollo Client's React integration, and it is not available in the core `ApolloClient` API. The default value is `false`.
`displayName` `string`	The name of your component to be displayed in the React Developer Tools. The default value is `Query`.
Networking options
`pollInterval` `number`	Specifies the interval (in milliseconds) at which the query polls for updated results. The default value is `0` (no polling).
`notifyOnNetworkStatusChange` `boolean`	If `true`, the in-progress query's associated component re-renders whenever the network status changes or a network error occurs. The default value is `false`.
`context` `Record<string, any>`	If you're using Apollo Link, this object is the initial value of the `context` object that's passed along your link chain.
`ssr` `boolean`	Pass `false` to skip executing the query during server-side rendering.
`client` `ApolloClient`	The instance of `ApolloClient` to use to execute the query. By default, the instance that's passed down via context is used, but you can provide a different instance here.
Caching options
`fetchPolicy` `FetchPolicy`	Specifies how the query interacts with the Apollo Client cache during execution (for example, whether it checks the cache for results before sending a request to the server). For details, see Setting a fetch policy. The default value is `cache-first`.
`nextFetchPolicy` `FetchPolicy`	Specifies the `fetchPolicy` to use for all executions of this query after this execution. For example, you can use this to switch back to a `cache-first` fetch policy after using `cache-and-network` or `network-only` for a single execution.
`returnPartialData` `boolean`	If `true`, the query can return partial results from the cache if the cache doesn't contain results for all queried fields. The default value is `false`.
Deprecated options
`partialRefetch` `boolean`	Deprecated. If `true`, causes a query `refetch` if the query result is detected as partial. Setting this option is unnecessary in Apollo Client 3, thanks to a more consistent application of fetch policies. It might be removed in a future release. The default value is `false`.

Operation options

`query`

DocumentNode

A GraphQL query string parsed into an AST with the gql template literal.

Optional for the useQuery hook, because the query can be provided as the first parameter to the hook. Required for the Query component.

`variables`

{ [key: string]: any }

An object containing all of the GraphQL variables your query requires to execute.

Each key in the object corresponds to a variable name, and that key's value corresponds to the variable value.

`errorPolicy`

ErrorPolicy

Specifies how the query handles a response that returns both GraphQL errors and partial results.

For details, see GraphQL error policies.

The default value is none, meaning that the query result includes error details but not partial results.

`onCompleted`

(data: TData | {}) => void

A callback function that's called when your query successfully completes with zero errors (or if errorPolicy is ignore and partial data is returned).

This function is passed the query's result data.

`onError`

(error: ApolloError) => void

A callback function that's called when the query encounters one or more errors (unless errorPolicy is ignore).

This function is passed an ApolloError object that contains either a networkError object or a graphQLErrors array, depending on the error(s) that occurred.

`skip`

boolean

If true, the query is not executed. Not available with useLazyQuery.

This property is part of Apollo Client's React integration, and it is not available in the core ApolloClient API.

The default value is false.

`displayName`

string

The name of your component to be displayed in the React Developer Tools.

The default value is Query.

Networking options

`pollInterval`

number

Specifies the interval (in milliseconds) at which the query polls for updated results.

The default value is 0 (no polling).

`notifyOnNetworkStatusChange`

boolean

If true, the in-progress query's associated component re-renders whenever the network status changes or a network error occurs.

The default value is false.

`context`

Record<string, any>

If you're using Apollo Link, this object is the initial value of the context object that's passed along your link chain.

`ssr`

boolean

Pass false to skip executing the query during server-side rendering.

`client`

ApolloClient

The instance of ApolloClient to use to execute the query.

By default, the instance that's passed down via context is used, but you can provide a different instance here.

Caching options

`fetchPolicy`

FetchPolicy

Specifies how the query interacts with the Apollo Client cache during execution (for example, whether it checks the cache for results before sending a request to the server).

For details, see Setting a fetch policy.

The default value is cache-first.

`nextFetchPolicy`

FetchPolicy

Specifies the fetchPolicy to use for all executions of this query after this execution.

For example, you can use this to switch back to a cache-first fetch policy after using cache-and-network or network-only for a single execution.

`returnPartialData`

boolean

If true, the query can return partial results from the cache if the cache doesn't contain results for all queried fields.

The default value is false.

Deprecated options

`partialRefetch`

boolean

The default value is false.

Result

Execute function

Param	Type	Description
Execute function	(options?: QueryLazyOptions<TVariables>) => void	Function that can be triggered to execute the suspended query. After being called, `useLazyQuery` behaves just like `useQuery`.

Result object

Name /
Type Description

Name / Type	Description
Operation data
`data` `TData`	An object containing the result of your GraphQL query after it completes. This value might be `undefined` if a query results in one or more errors (depending on the query's `errorPolicy`).
`previousData` `TData`	An object containing the result from the most recent previous execution of this query. This value is `undefined` if this is the query's first execution.
`error` `ApolloError`	If the query produces one or more errors, this object contains either an array of `graphQLErrors` or a single `networkError`. Otherwise, this value is `undefined`. For more information, see Handling operation errors.
`variables` `{ [key: string]: any }`	An object containing the variables that were provided for the query.
Network info
`loading` `boolean`	If `true`, the query is still in flight and results have not yet been returned.
`networkStatus` `NetworkStatus`	A number indicating the current network state of the query's associated request. See possible values. Used in conjunction with the `notifyOnNetworkStatusChange` option.
`client` `ApolloClient`	The instance of Apollo Client that executed the query. Can be useful for manually executing followup queries or writing data to the cache.
`called` `boolean`	If `true`, the associated lazy query has been executed. This field is only present on the result object returned by `useLazyQuery`.
Helper functions
`refetch` `(variables?: Partial<TVariables>) => Promise<ApolloQueryResult>`	A function that enables you to re-execute the query, optionally passing in new `variables`. The followup execution's `fetchPolicy` is set to `network-only` if the original query's `fetchPolicy` isn't guaranteed to send a network request (such as with `cache-first`). See also Refetching.
`fetchMore` `({ query?: DocumentNode, variables?: TVariables, updateQuery: Function}) => Promise<ApolloQueryResult>`	A function that helps you fetch the next set of results for a paginated list field.
`startPolling` `(interval: number) => void`	A function that instructs the query to begin re-executing at a specified interval (in milliseconds).
`stopPolling` `() => void`	A function that instructs the query to stop polling after a previous call to `startPolling`.
`subscribeToMore` `(options: { document: DocumentNode, variables?: TVariables, updateQuery?: Function, onError?: Function}) => () => void`	A function that enables you to execute a subscription, usually to subscribe to specific fields that were included in the query. This function returns another function that you can call to terminate the subscription.
`updateQuery` `(previousResult: TData, options: { variables: TVariables }) => TData`	A function that enables you to update the query's cached result without executing a followup GraphQL operation.

Operation data

`data`

TData

An object containing the result of your GraphQL query after it completes.

This value might be undefined if a query results in one or more errors (depending on the query's errorPolicy).

`previousData`

TData

An object containing the result from the most recent previous execution of this query.

This value is undefined if this is the query's first execution.

`error`

ApolloError

If the query produces one or more errors, this object contains either an array of graphQLErrors or a single networkError. Otherwise, this value is undefined.

For more information, see Handling operation errors.

`variables`

{ [key: string]: any }

An object containing the variables that were provided for the query.

Network info

`loading`

boolean

If true, the query is still in flight and results have not yet been returned.

`networkStatus`

NetworkStatus

A number indicating the current network state of the query's associated request. See possible values.

Used in conjunction with the notifyOnNetworkStatusChange option.

`client`

ApolloClient

The instance of Apollo Client that executed the query.

Can be useful for manually executing followup queries or writing data to the cache.

`called`

boolean

If true, the associated lazy query has been executed.

This field is only present on the result object returned by useLazyQuery.

Helper functions

`refetch`

(variables?: Partial<TVariables>) => Promise<ApolloQueryResult>

A function that enables you to re-execute the query, optionally passing in new variables.

The followup execution's fetchPolicy is set to network-only if the original query's fetchPolicy isn't guaranteed to send a network request (such as with cache-first).

This function returns another function that you can call to terminate the subscription.

import { gql, useMutation } from '@apollo/client';

const ADD_TODO = gql`
  mutation AddTodo($type: String!) {
    addTodo(type: $type) {
      id
      type
    }
  }
`;

function AddTodo() {
  let input;
  const [addTodo, { data }] = useMutation(ADD_TODO);

  return (
    <div>
      <form
        onSubmit={e => {
          e.preventDefault();
          addTodo({ variables: { type: input.value } });
          input.value = '';
        }}
      >
        <input
          ref={node => {
            input = node;
          }}
        />
        <button type="submit">Add Todo</button>
      </form>
    </div>
  );
}

Refer to the Mutations section for a more in-depth overview of useMutation.

Function Signature

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

Params

`mutation`

Param	Type	Description
`mutation`	DocumentNode	A GraphQL mutation document parsed into an AST by `gql`.

`options`

Option	Type	Description
`mutation`	DocumentNode	A GraphQL mutation document parsed into an AST by `graphql-tag`. Optional for the `useMutation` Hook since the mutation can be passed in as the first parameter to the Hook. Required for the `Mutation` component.
`variables`	{ [key: string]: any }	An object containing all of the variables your mutation needs to execute
`update`	(cache: DataProxy, mutationResult: FetchResult)	A function used to update the cache after a mutation occurs
`ignoreResults`	boolean	If true, the returned `data` property will not update with the mutation result.
`optimisticResponse`	Object	Provide a mutation response before the result comes back from the server
`refetchQueries`	Array<string\|{ query: DocumentNode, variables?: TVariables}> \| ((mutationResult: FetchResult) => Array<string\|{ query: DocumentNode, variables?: TVariables}>)	An array or function that allows you to specify which queries you want to refetch after a mutation has occurred. Array values can either be queries (with optional variables) or just the string names of queries to be refeteched.
`awaitRefetchQueries`	boolean	Queries refetched as part of `refetchQueries` are handled asynchronously, and are not waited on before the mutation is completed (resolved). Setting this to `true` will make sure refetched queries are completed before the mutation is considered done. `false` by default.
`onCompleted`	(data: TData) => void	A callback executed once your mutation successfully completes
`onError`	(error: ApolloError) => void	A callback executed in the event of an error.
`context`	Record<string, any>	Shared context between your component and your network interface (Apollo Link). Useful for setting headers from props or sending information to the `request` function of Apollo Boost.
`client`	ApolloClient	An `ApolloClient` instance. By default `useMutation` / `Mutation` uses the client passed down via context, but a different client can be passed in.

Result

Mutate function:

Property	Type	Description
`mutate`	(options?: MutationOptions) => Promise<FetchResult>	A function to trigger a mutation from your UI. You can optionally pass `variables`, `optimisticResponse`, `refetchQueries`, and `update` in as options, which will override options/props passed to `useMutation` / `Mutation`. The function returns a promise that fulfills with your mutation result.

Mutation result:

Property	Type	Description
`data`	TData	The data returned from your mutation. It can be undefined if `ignoreResults` is true.
`loading`	boolean	A boolean indicating whether your mutation is in flight
`error`	ApolloError	Any errors returned from the mutation
`called`	boolean	A boolean indicating if the mutate function has been called
`client`	ApolloClient	Your `ApolloClient` instance. Useful for invoking cache methods outside the context of the update function, such as `client.writeData` and `client.readQuery`.

`useSubscription`

Example

const COMMENTS_SUBSCRIPTION = gql`
  subscription OnCommentAdded($repoFullName: String!) {
    commentAdded(repoFullName: $repoFullName) {
      id
      content
    }
  }
`;

function DontReadTheComments({ repoFullName }) {
  const {
    data: { commentAdded },
    loading,
  } = useSubscription(COMMENTS_SUBSCRIPTION, { variables: { repoFullName } });
  return <h4>New comment: {!loading && commentAdded.content}</h4>;
}

Refer to the Subscriptions section for a more in-depth overview of useSubscription.

Function Signature

function useSubscription<TData = any, TVariables = OperationVariables>(
  subscription: DocumentNode,
  options?: SubscriptionHookOptions<TData, TVariables>,
): {
  variables: TVariables;
  loading: boolean;
  data?: TData;
  error?: ApolloError;
} {}

Params

`subscription`

Param	Type	Description
`subscription`	DocumentNode	A GraphQL subscription document parsed into an AST by `gql`.

`options`

Option	Type	Description
`subscription`	DocumentNode	A GraphQL subscription document parsed into an AST by `graphql-tag`. Optional for the `useSubscription` Hook since the subscription can be passed in as the first parameter to the Hook. Required for the `Subscription` component.
`variables`	{ [key: string]: any }	An object containing all of the variables your subscription needs to execute
`shouldResubscribe`	boolean	Determines if your subscription should be unsubscribed and subscribed again
`skip`	boolean	If `skip` is `true`, the subscription will be skipped entirely
`onSubscriptionData`	(options: OnSubscriptionDataOptions<TData>) => any	Allows the registration of a callback function, that will be triggered each time the `useSubscription` Hook / `Subscription` component receives data. The callback `options` object param consists of the current Apollo Client instance in `client`, and the received subscription data in `subscriptionData`.
`fetchPolicy`	FetchPolicy	How you want your component to interact with the Apollo cache. Defaults to "cache-first".
`client`	ApolloClient	An `ApolloClient` instance. By default `useSubscription` / `Subscription` uses the client passed down via context, but a different client can be passed in.

Result

Property	Type	Description
`data`	TData	An object containing the result of your GraphQL subscription. Defaults to an empty object.
`loading`	boolean	A boolean that indicates whether any initial data has been returned
`error`	ApolloError	A runtime error with `graphQLErrors` and `networkError` properties

`useApolloClient`

Example

import { useApolloClient } from '@apollo/client';

function SomeComponent() {
  const client = useApolloClient();
  // `client` is now set to the `ApolloClient` instance being used by the
  // application (that was configured using something like `ApolloProvider`)
}

Function Signature

function useApolloClient(): ApolloClient<object> {}

Result

Param	Type	Description
Apollo Client instance	ApolloClient<object>	The `ApolloClient` instance being used by the application.

Hooks

Apollo Client react hooks API reference