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class ApolloClient

API reference


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 103)

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
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.

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.

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

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
fetchPolicy

"cache-first" | "network-only" | "cache-only" | "no-cache" | "standby" | "cache-and-network"

Specifies the FetchPolicy to be used for this query.

nextFetchPolicy

any

Specifies the FetchPolicy to be used after this query has completed.

refetchWritePolicy

"merge" | "overwrite"

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.

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

"none" | "ignore" | "all"

Specifies the ErrorPolicy to be used for this query

fetchPolicy

"cache-first" | "network-only" | "cache-only" | "no-cache" | "standby"

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.

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

"none" | "ignore" | "all"

Specifies the ErrorPolicy to be used for this operation

fetchPolicy

Extract<"cache-first" | "network-only" | "cache-only" | "no-cache" | "standby", "network-only" | "no-cache">

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

(any, Omit<FetchResult, "context">, any) => any<, , , >

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<, ><><>

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.

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

"none" | "ignore" | "all"

Specifies the ErrorPolicy to be used for this operation

fetchPolicy

"cache-first" | "network-only" | "cache-only" | "no-cache" | "standby"

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.

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
optimistic

any

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

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
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.

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

any

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.

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

any

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.

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.

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
cb

() => Promise<>

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

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
cb

() => Promise<>

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

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
includeStandby

any

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

any

Types

Properties
Name /
Type
Description
assumeImmutableResults

any

cache

ApolloCache<>

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

Properties
Name /
Type
Description
mutate

Partial<MutationOptions>

query

Partial<QueryOptions>

watchQuery

Partial<WatchQueryOptions>

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