class ApolloClient

Launch Apollo Studio

The ApolloClient class encapsulates Apollo's core client-side API. It backs all available view-layer integrations (React, iOS, and so on).

The `ApolloClient` constructor

`constructor(options)`

(src/core/ApolloClient.ts, line 141)

Constructs an instance of ApolloClient.

Takes an ApolloClientOptions parameter that supports the fields listed below.

Returns an initialized ApolloClient object.

Example

import { ApolloClient, InMemoryCache } from '@apollo/client';

const cache = new InMemoryCache();

const client = new ApolloClient({
  // Provide required constructor fields
  cache: cache,
  uri: 'http://localhost:4000/',

  // Provide some optional constructor fields
  name: 'react-web-client',
  version: '1.3',
  queryDeduplication: false,
  defaultOptions: {
    watchQuery: {
      fetchPolicy: 'cache-and-network',
    },
  },
});

Options

Name /
Type Description

Name / Type	Description
`uri` `String`	The URI of the GraphQL endpoint that Apollo Client will communicate with. One of `uri` or `link` is required. If you provide both, `link` takes precedence.
`link` `ApolloLink`	You can provide an Apollo Link instance to serve as Apollo Client's network layer. For more information, see Advanced HTTP networking. One of `uri` or `link` is required. If you provide both, `link` takes precedence.
`cache` `ApolloCache` (usually `InMemoryCache`)	Required. The cache that Apollo Client should use to store query results locally. The recommended cache is `InMemoryCache`, which is provided by the `@apollo/client` package. For more information, see Configuring the cache.
`name` `String`	A custom name (e.g., `iOS`) that identifies this particular client among your set of clients. Apollo Server and Apollo Studio use this property as part of the client awareness feature.
`version` `String`	A custom version that identifies the current version of this particular client (e.g., `1.2`). Apollo Server and Apollo Studio use this property as part of the client awareness feature. This is not the version of Apollo Client that you are using, but rather any version string that helps you differentiate between versions of your client.
`ssrMode` `Boolean`	When using Apollo Client for server-side rendering, set this to `true` so that the `getDataFromTree` function can work effectively. The default value is `false`.
`ssrForceFetchDelay` `Number`	The time interval (in milliseconds) before Apollo Client force-fetches queries after a server-side render. The default value is `0` (no delay).
`connectToDevTools` `Boolean`	If `true`, the Apollo Client Devtools browser extension can connect to Apollo Client in your production environment. The extension can always connect in a non-production environment. The default value is `false`.
`queryDeduplication` `Boolean`	If `false`, Apollo Client sends every created query to the server, even if a completely identical query (identical in terms of query string, variable values, and operationName) is already in flight. The default value is `true`.
`defaultOptions` `Object`	Provide this object to set application-wide default values for options you can provide to the `watchQuery`, `query`, and `mutate` functions. See below for an example object. See the example object below.

`uri`

String

The URI of the GraphQL endpoint that Apollo Client will communicate with.

One of uri or link is required. If you provide both, link takes precedence.

`link`

ApolloLink

You can provide an Apollo Link instance to serve as Apollo Client's network layer. For more information, see Advanced HTTP networking.

One of uri or link is required. If you provide both, link takes precedence.

`cache`

ApolloCache (usually InMemoryCache)

Required. The cache that Apollo Client should use to store query results locally. The recommended cache is InMemoryCache, which is provided by the @apollo/client package.

For more information, see Configuring the cache.

`name`

String

A custom name (e.g., iOS) that identifies this particular client among your set of clients. Apollo Server and Apollo Studio use this property as part of the client awareness feature.

`version`

String

A custom version that identifies the current version of this particular client (e.g., 1.2). Apollo Server and Apollo Studio use this property as part of the client awareness feature.

This is not the version of Apollo Client that you are using, but rather any version string that helps you differentiate between versions of your client.

`ssrMode`

Boolean

When using Apollo Client for server-side rendering, set this to true so that the getDataFromTree function can work effectively.

The default value is false.

`ssrForceFetchDelay`

Number

The time interval (in milliseconds) before Apollo Client force-fetches queries after a server-side render.

The default value is 0 (no delay).

`connectToDevTools`

Boolean

If true, the Apollo Client Devtools browser extension can connect to Apollo Client in your production environment. The extension can always connect in a non-production environment.

The default value is false.

If false, Apollo Client sends every created query to the server, even if a completely identical query (identical in terms of query string, variable values, and operationName) is already in flight.

The default value is true.

`defaultOptions`

Object

Provide this object to set application-wide default values for options you can provide to the watchQuery, query, and mutate functions. See below for an example object.

See the example object below.

Example `defaultOptions` object

const defaultOptions = {
  watchQuery: {
    fetchPolicy: 'cache-and-network',
    errorPolicy: 'ignore',
  },
  query: {
    fetchPolicy: 'network-only',
    errorPolicy: 'all',
  },
  mutate: {
    errorPolicy: 'all',
  },
};

You can override any default option you specify in this object by providing a different value for the same option in individual function calls.

Note: The useQuery hook uses Apollo Client's watchQuery function. To set defaultOptions when using the useQuery hook, make sure to set them under the defaultOptions.watchQuery property.

Functions

`watchQuery(options): ObservableQuery<T, TVariables>`

(src/core/ApolloClient.ts, line 299)

This watches the cache store of the query according to the options specified and returns an ObservableQuery. We can subscribe to this ObservableQuery and receive updated results through a GraphQL observer when the cache store changes.

Options

Name / Type	Description
`canonizeResults` `any`	Whether to canonize cache results before returning them. Canonization takes some extra time, but it speeds up future deep equality comparisons. Defaults to false.
`context` `any`	Context to be passed to link execution chain
`errorPolicy` `any`	Specifies the ErrorPolicy to be used for this query
`fetchPolicy` `any`	Specifies the FetchPolicy to be used for this query.
`nextFetchPolicy` `any`	Specifies the FetchPolicy to be used after this query has completed.
`notifyOnNetworkStatusChange` `any`	Whether or not updates to the network status should trigger next on the observer of this query
`partialRefetch` `any`	If `true`, perform a query `refetch` if the query result is marked as being partial, and the returned data is reset to an empty Object by the Apollo Client `QueryManager` (due to a cache miss).
`pollInterval` `any`	The time interval (in milliseconds) on which this query should be refetched from the server.
`query` `DocumentNode \| TypedDocumentNode`	A GraphQL document that consists of a single query to be sent down to the server.
`refetchWritePolicy` `RefetchWritePolicy`	Specifies whether a {@link NetworkStatus.refetch} operation should merge incoming field data with existing data, or overwrite the existing data. Overwriting is probably preferable, but merging is currently the default behavior, for backwards compatibility with Apollo Client 3.x.
`returnPartialData` `any`	Allow returning incomplete data from the cache when a larger query cannot be fully satisfied by the cache, instead of returning nothing.
`variables` `TVariables`	A map going from variable name to variable value, where the variables are used within the GraphQL query.

`query(options): Promise<ApolloQueryResult>`

(src/core/ApolloClient.ts, line 327)

This resolves a single query according to the options specified and returns a Promise which is either resolved with the resulting data or rejected with an error.

Options

Name / Type	Description
`canonizeResults` `any`	Whether to canonize cache results before returning them. Canonization takes some extra time, but it speeds up future deep equality comparisons. Defaults to false.
`context` `any`	Context to be passed to link execution chain
`errorPolicy` `any`	Specifies the ErrorPolicy to be used for this query
`fetchPolicy` `any`	Specifies the FetchPolicy to be used for this query
`notifyOnNetworkStatusChange` `any`	Whether or not updates to the network status should trigger next on the observer of this query
`partialRefetch` `any`	If `true`, perform a query `refetch` if the query result is marked as being partial, and the returned data is reset to an empty Object by the Apollo Client `QueryManager` (due to a cache miss).
`pollInterval` `any`	The time interval (in milliseconds) on which this query should be refetched from the server.
`query` `DocumentNode \| TypedDocumentNode`	A GraphQL document that consists of a single query to be sent down to the server.
`returnPartialData` `any`	Allow returning incomplete data from the cache when a larger query cannot be fully satisfied by the cache, instead of returning nothing.
`variables` `TVariables`	A map going from variable name to variable value, where the variables are used within the GraphQL query.

`mutate(options): Promise<FetchResult>`

(src/core/ApolloClient.ts, line 356)

This resolves a single mutation according to the options specified and returns a Promise which is either resolved with the resulting data or rejected with an error.

It takes options as an object with the following keys and values:

Options

Name / Type	Description
`awaitRefetchQueries` `any`	By default, `refetchQueries` does not wait for the refetched queries to be completed, before resolving the mutation `Promise`. This ensures that query refetching does not hold up mutation response handling (query refetching is handled asynchronously). Set `awaitRefetchQueries` to `true` if you would like to wait for the refetched queries to complete, before the mutation can be marked as resolved.
`context` `TContext`	The context to be passed to the link execution chain. This context will only be used with this mutation. It will not be used with `refetchQueries`. Refetched queries use the context they were initialized with (since the initial context is stored as part of the `ObservableQuery` instance). If a specific context is needed when refetching queries, make sure it is configured (via the query `context` option) when the query is first initialized/run.
`errorPolicy` `any`	Specifies the ErrorPolicy to be used for this operation
`fetchPolicy` `MutationFetchPolicy`	Specifies the MutationFetchPolicy to be used for this query. Mutations support only 'network-only' and 'no-cache' fetchPolicy strings. If fetchPolicy is not provided, it defaults to 'network-only'.
`keepRootFields` `any`	To avoid retaining sensitive information from mutation root field arguments, Apollo Client v3.4+ automatically clears any `ROOT_MUTATION` fields from the cache after each mutation finishes. If you need this information to remain in the cache, you can prevent the removal by passing `keepRootFields: true` to the mutation. `ROOT_MUTATION` result data are also passed to the mutation `update` function, so we recommend obtaining the results that way, rather than using this option, if possible.
`mutation` `DocumentNode \| TypedDocumentNode`	A GraphQL document, often created with `gql` from the `graphql-tag` package, that contains a single mutation inside of it.
`onQueryUpdated` `(ObservableQuery<>, Cache.DiffResult<>, any) => any<>`	A function that will be called for each ObservableQuery affected by this mutation, after the mutation has completed.
`optimisticResponse` `any`	An object that represents the result of this mutation that will be optimistically stored before the server has actually returned a result. This is most often used for optimistic UI, where we want to be able to see the result of a mutation immediately, and update the UI later if any errors appear.
`refetchQueries` `any`	A list of query names which will be refetched once this mutation has returned. This is often used if you have a set of queries which may be affected by a mutation and will have to update. Rather than writing a mutation query reducer (i.e. `updateQueries`) for this, you can simply refetch the queries that will be affected and achieve a consistent store once these queries return.
`update` `(TCache, Omit<FetchResult, >, any) => any<TData, TVariables, TContext, TCache>`	This function will be called twice over the lifecycle of a mutation. Once at the very beginning if an `optimisticResponse` was provided. The writes created from the optimistic data will be rolled back before the second time this function is called which is when the mutation has successfully resolved. At that point `update` will be called with the actual mutation result and those writes will not be rolled back. Note that since this function is intended to be used to update the store, it cannot be used with a `no-cache` fetch policy. If you're interested in performing some action after a mutation has completed, and you don't need to update the store, use the Promise returned from `client.mutate` instead.
`updateQueries` `[queryName:undefined]:(Record<, >, any) => Record<, ><T><TData>`	A MutationQueryReducersMap, which is map from query names to mutation query reducers. Briefly, this map defines how to incorporate the results of the mutation into the results of queries that are currently being watched by your application.
`variables` `TVariables`	An object that maps from the name of a variable as used in the mutation GraphQL document to that variable's value.

`subscribe(options): Observable<FetchResult>`

(src/core/ApolloClient.ts, line 374)

This subscribes to a graphql subscription according to the options specified and returns an Observable which either emits received data or an error.

Options

Name / Type	Description
`context` `Record<, >`	Context object to be passed through the link execution chain.
`errorPolicy` `any`	Specifies the ErrorPolicy to be used for this operation
`fetchPolicy` `any`	Specifies the FetchPolicy to be used for this subscription.
`query` `DocumentNode \| TypedDocumentNode`	A GraphQL document, often created with `gql` from the `graphql-tag` package, that contains a single subscription inside of it.
`variables` `TVariables`	An object that maps from the name of a variable as used in the subscription GraphQL document to that variable's value.

`readQuery(options, optimistic): any`

(src/core/ApolloClient.ts, line 389)

Tries to read some data from the store in the shape of the provided GraphQL query without making a network request. This method will start at the root query. To start at a specific id returned by dataIdFromObject use readFragment.

Arguments

Name /
Type Description

Name / Type	Description
`optimistic` `any`	Set to `true` to allow `readQuery` to return optimistic results. Is `false` by default.

`optimistic`

any

Set to true to allow readQuery to return optimistic results. Is false by default.

`readFragment(options, optimistic): any`

(src/core/ApolloClient.ts, line 410)

Tries to read some data from the store in the shape of the provided GraphQL fragment without making a network request. This method will read a GraphQL fragment from any arbitrary id that is currently cached, unlike readQuery which will only read from the root query.

You must pass in a GraphQL document with a single fragment or a document with multiple fragments that represent what you are reading. If you pass in a document with multiple fragments then you must also specify a fragmentName.

Arguments

Name /
Type Description

Name / Type	Description
`optimistic` `any`	Set to `true` to allow `readFragment` to return optimistic results. Is `false` by default.

`optimistic`

any

Set to true to allow readFragment to return optimistic results. Is false by default.

Options

Name / Type	Description
`fragment` `DocumentNode \| TypedDocumentNode`	A GraphQL document created using the `gql` template string tag from `graphql-tag` with one or more fragments which will be used to determine the shape of data to read. If you provide more than one fragment in this document then you must also specify `fragmentName` to select a single.
`fragmentName` `any`	The name of the fragment in your GraphQL document to be used. If you do not provide a `fragmentName` and there is only one fragment in your `fragment` document then that fragment will be used.
`id` `any`	The root id to be used. This id should take the same form as the value returned by your `dataIdFromObject` function. If a value with your id does not exist in the store, `null` will be returned.
`variables` `TVariables`	Any variables that your GraphQL fragments depend on.

`writeQuery(options): any`

(src/core/ApolloClient.ts, line 422)

Writes some data in the shape of the provided GraphQL query directly to the store. This method will start at the root query. To start at a specific id returned by dataIdFromObject then use writeFragment.

Options

Name / Type	Description
`broadcast` `any`	Whether to notify query watchers (default: true).
`data` `TData`	The data you will be writing to the store.
`id` `any`	The root id to be used. Defaults to "ROOT_QUERY", which is the ID of the root query object. This property makes writeQuery capable of writing data to any object in the cache.
`overwrite` `any`	When true, ignore existing field data rather than merging it with incoming data (default: false).
`query` `DocumentNode \| TypedDocumentNode`	The GraphQL query shape to be used constructed using the `gql` template string tag from `graphql-tag`. The query will be used to determine the shape of the data to be read.
`variables` `TVariables`	Any variables that the GraphQL query may depend on.

`writeFragment(options): any`

(src/core/ApolloClient.ts, line 440)

Writes some data in the shape of the provided GraphQL fragment directly to the store. This method will write to a GraphQL fragment from any arbitrary id that is currently cached, unlike writeQuery which will only write from the root query.

You must pass in a GraphQL document with a single fragment or a document with multiple fragments that represent what you are writing. If you pass in a document with multiple fragments then you must also specify a fragmentName.

Options

Name / Type	Description
`broadcast` `any`	Whether to notify query watchers (default: true).
`data` `TData`	The data you will be writing to the store.
`fragment` `DocumentNode \| TypedDocumentNode`	A GraphQL document created using the `gql` template string tag from `graphql-tag` with one or more fragments which will be used to determine the shape of data to read. If you provide more than one fragment in this document then you must also specify `fragmentName` to select a single.
`fragmentName` `any`	The name of the fragment in your GraphQL document to be used. If you do not provide a `fragmentName` and there is only one fragment in your `fragment` document then that fragment will be used.
`id` `any`	The root id to be used. This id should take the same form as the value returned by your `dataIdFromObject` function. If a value with your id does not exist in the store, `null` will be returned.
`overwrite` `any`	When true, ignore existing field data rather than merging it with incoming data (default: false).
`variables` `TVariables`	Any variables that your GraphQL fragments depend on.

`resetStore(): Promise<>`

(src/core/ApolloClient.ts, line 471)

Resets your entire store by clearing out your cache and then re-executing all of your active queries. This makes it so that you may guarantee that there is no data left in your store from a time before you called this method.

resetStore() is useful when your user just logged out. You’ve removed the user session, and you now want to make sure that any references to data you might have fetched while the user session was active is gone.

It is important to remember that resetStore() will refetch any active queries. This means that any components that might be mounted will execute their queries again using your network interface. If you do not want to re-execute any queries then you should make sure to stop watching any active queries.

`onResetStore(cb): () => any`

(src/core/ApolloClient.ts, line 497)

Allows callbacks to be registered that are executed when the store is reset. onResetStore returns an unsubscribe function that can be used to remove registered callbacks.

Arguments

Name /
Type Description

Name / Type	Description
`cb` `() => Promise<>`

`cb`

() => Promise<>

`clearStore(): Promise<>`

(src/core/ApolloClient.ts, line 484)

Remove all data from the store. Unlike resetStore, clearStore will not refetch any active queries.

`onClearStore(cb): () => any`

(src/core/ApolloClient.ts, line 509)

Allows callbacks to be registered that are executed when the store is cleared. onClearStore returns an unsubscribe function that can be used to remove registered callbacks.

Arguments

Name /
Type Description

Name / Type	Description
`cb` `() => Promise<>`

`cb`

() => Promise<>

`stop(): any`

(src/core/ApolloClient.ts, line 276)

Call this method to terminate any active client processes, making it safe to dispose of this ApolloClient instance.

`reFetchObservableQueries(includeStandby): Promise<>`

(src/core/ApolloClient.ts, line 528)

Refetches all of your active queries.

reFetchObservableQueries() is useful if you want to bring the client back to proper state in case of a network outage

It is important to remember that reFetchObservableQueries() will refetch any active queries. This means that any components that might be mounted will execute their queries again using your network interface. If you do not want to re-execute any queries then you should make sure to stop watching any active queries. Takes optional parameter includeStandby which will include queries in standby-mode when refetching.

Arguments

Name /
Type Description

Name / Type	Description
`includeStandby` `any`

`includeStandby`

any

`refetchQueries(options): RefetchQueriesResult<TResult>`

(src/core/ApolloClient.ts, line 545)

Refetches specified active queries. Similar to "reFetchObservableQueries()" but with a specific list of queries.

refetchQueries() is useful for use cases to imperatively refresh a selection of queries.

It is important to remember that refetchQueries() will refetch specified active queries. This means that any components that might be mounted will execute their queries again using your network interface. If you do not want to re-execute any queries then you should make sure to stop watching any active queries.

Options

Name / Type	Description
`include` `any`
`onQueryUpdated` `any`
`optimistic` `any`
`updateCache` `(TCache) => any`

Properties

Name / Type	Description
`assumeImmutableResults` `any`
`cache` `ApolloCache<TCacheShape>`
`connectToDevTools` `any`
`credentials` `any`
`defaultOptions` `DefaultOptions`
`fragmentMatcher` `(any, any, any) => any`
`headers` `Record<, >`
`link` `ApolloLink`
`name` `any`
`queryDeduplication` `any`
`resolvers` `any`
`ssrForceFetchDelay` `any`
`ssrMode` `any`
`typeDefs` `any`
`uri` `any`
`version` `any`

`DefaultOptions`

(src/core/ApolloClient.ts, line 38)

Properties

Name /
Type Description

Name / Type	Description
`mutate` `Partial<MutationOptions>`
`query` `Partial<QueryOptions>`
`watchQuery` `Partial<WatchQueryOptions>`

`mutate`

Partial<MutationOptions>

`query`

Partial<QueryOptions>

`watchQuery`

Partial<WatchQueryOptions>

class ApolloClient

API reference

.css-2inqlj{padding:0 !important;background:none !important;}constructor(options)

Options

canonizeResults

context

errorPolicy

fetchPolicy

nextFetchPolicy

notifyOnNetworkStatusChange

partialRefetch

pollInterval

query

refetchWritePolicy

returnPartialData

variables

Options

canonizeResults

context

errorPolicy

fetchPolicy

notifyOnNetworkStatusChange

partialRefetch

pollInterval

query

returnPartialData

variables

Options

awaitRefetchQueries

context

errorPolicy

fetchPolicy

keepRootFields

mutation

onQueryUpdated

optimisticResponse

refetchQueries

update

updateQueries

variables

Options

context

errorPolicy

fetchPolicy

query

variables

Arguments

optimistic

Arguments

optimistic

Options

fragment

fragmentName

id

variables

Options

broadcast

data

id

overwrite

query

variables

Options

broadcast

data

fragment

fragmentName

id

overwrite

variables

Arguments

cb

Arguments

cb

Arguments

includeStandby

Options

include

onQueryUpdated

optimistic

`constructor(options)`

`canonizeResults`

`context`

`errorPolicy`

`fetchPolicy`

`nextFetchPolicy`

`notifyOnNetworkStatusChange`

`partialRefetch`

`pollInterval`

`query`

`refetchWritePolicy`

`returnPartialData`

`variables`

`canonizeResults`

`context`

`errorPolicy`

`fetchPolicy`

`notifyOnNetworkStatusChange`

`partialRefetch`

`pollInterval`

`query`

`returnPartialData`

`variables`

`awaitRefetchQueries`

`context`

`errorPolicy`

`fetchPolicy`

`keepRootFields`

`mutation`

`onQueryUpdated`

`optimisticResponse`

`refetchQueries`

`update`

`updateQueries`

`variables`

`context`

`errorPolicy`

`fetchPolicy`

`query`

`variables`

`optimistic`

`optimistic`

`fragment`

`fragmentName`

`id`

`variables`

`broadcast`

`data`

`id`

`overwrite`

`query`

`variables`

`broadcast`

`data`

`fragment`

`fragmentName`

`id`

`overwrite`

`variables`

`cb`

`cb`

`includeStandby`

`include`

`onQueryUpdated`

`optimistic`

`updateCache`

`assumeImmutableResults`

`cache`

`connectToDevTools`

`credentials`

`defaultOptions`

`fragmentMatcher`

`headers`

`link`

`name`

`queryDeduplication`

`resolvers`

`ssrForceFetchDelay`

`ssrMode`

`typeDefs`