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
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 fieldscache: cache,uri: 'http://localhost:4000/',// Provide some optional constructor fieldsname: 'react-web-client',version: '1.3',queryDeduplication: false,defaultOptions: {watchQuery: {fetchPolicy: 'cache-and-network',},},});
For more information on the defaultOptions object, see the Default Options section below.
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.
Note that this method is not an implementation of GraphQL subscriptions. Rather, it uses Apollo's store in order to reactively deliver updates to your query results.
For example, suppose you call watchQuery on a GraphQL query that fetches a person's first and last name and this person has a particular object identifier, provided by dataIdFromObject. Later, a different query fetches that same person's first and last name and the first name has now changed. Then, any observers associated with the results of the first query will be updated with a new result object.
Note that if the cache does not change, the subscriber will not be notified.
See here for a description of store reactivity.
Parameters
options
WatchQueryOptions<TVariables, T>Show/hide child attributes
options.canonizeResults (optional)
booleanWhether to canonize cache results before returning them. Canonization takes some extra time, but it speeds up future deep equality comparisons. Defaults to false.
options.context (optional)
DefaultContextContext to be passed to link execution chain
options.errorPolicy (optional)
ErrorPolicySpecifies the ErrorPolicy to be used for this query
options.fetchPolicy (optional)
WatchQueryFetchPolicySpecifies the FetchPolicy to be used for this query.
options.initialFetchPolicy (optional)
WatchQueryFetchPolicyDefaults to the initial value of options.fetchPolicy, but can be explicitly configured to specify the WatchQueryFetchPolicy to revert back to whenever variables change (unless nextFetchPolicy intervenes).
options.nextFetchPolicy (optional)
WatchQueryFetchPolicy | ((this: WatchQueryOptions<TVariables, TData>, currentFetchPolicy: WatchQueryFetchPolicy, context: NextFetchPolicyContext<TData, TVariables>) => WatchQueryFetchPolicy)Specifies the FetchPolicy to be used after this query has completed.
options.notifyOnNetworkStatusChange (optional)
booleanWhether or not updates to the network status should trigger next on the observer of this query
options.partialRefetch (optional)
booleanIf 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).
options.pollInterval (optional)
numberThe time interval (in milliseconds) on which this query should be refetched from the server.
options.query
DocumentNode | TypedDocumentNode<TData, TVariables>A GraphQL document that consists of a single query to be sent down to the server.
options.refetchWritePolicy (optional)
RefetchWritePolicySpecifies 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.
options.returnPartialData (optional)
booleanAllow returning incomplete data from the cache when a larger query cannot be fully satisfied by the cache, instead of returning nothing.
options.variables (optional)
TVariablesA map going from variable name to variable value, where the variables are used within the GraphQL query.
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.
Parameters
options
QueryOptions<TVariables, T>An object of type QueryOptions that allows us to describe how this query should be treated e.g. whether it should hit the server at all or just resolve from the cache, etc.
Show/hide child attributes
options.canonizeResults (optional)
booleanWhether to canonize cache results before returning them. Canonization takes some extra time, but it speeds up future deep equality comparisons. Defaults to false.
options.context (optional)
DefaultContextContext to be passed to link execution chain
options.errorPolicy (optional)
ErrorPolicySpecifies the ErrorPolicy to be used for this query
options.fetchPolicy (optional)
FetchPolicySpecifies the FetchPolicy to be used for this query
options.notifyOnNetworkStatusChange (optional)
booleanWhether or not updates to the network status should trigger next on the observer of this query
options.partialRefetch (optional)
booleanIf 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).
options.pollInterval (optional)
numberThe time interval (in milliseconds) on which this query should be refetched from the server.
options.query
DocumentNode | TypedDocumentNode<TData, TVariables>A GraphQL document that consists of a single query to be sent down to the server.
options.returnPartialData (optional)
booleanAllow returning incomplete data from the cache when a larger query cannot be fully satisfied by the cache, instead of returning nothing.
options.variables (optional)
TVariablesA 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:
Parameters
options
MutationOptions<TData, TVariables, TContext>Show/hide child attributes
options.awaitRefetchQueries (optional)
booleanBy 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.
options.context (optional)
TContextThe 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.
options.errorPolicy (optional)
ErrorPolicySpecifies the ErrorPolicy to be used for this operation
options.fetchPolicy (optional)
MutationFetchPolicySpecifies 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'.
options.keepRootFields (optional)
booleanTo 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.
options.mutation
DocumentNode | TypedDocumentNode<TData, TVariables>A GraphQL document, often created with gql from the graphql-tag package, that contains a single mutation inside of it.
options.onQueryUpdated (optional)
OnQueryUpdated<any>A function that will be called for each ObservableQuery affected by this mutation, after the mutation has completed.
options.optimisticResponse (optional)
TData | ((vars: TVariables) => TData)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.
options.refetchQueries (optional)
((result: FetchResult<TData>) => InternalRefetchQueriesInclude) | InternalRefetchQueriesIncludeA 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.
options.update (optional)
MutationUpdaterFunction<TData, TVariables, TContext, TCache>A function which provides an ApolloCache instance, and the result of the mutation, to allow the user to update the store based on the results of the mutation.
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.
options.updateQueries (optional)
MutationQueryReducersMap<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.
options.variables (optional)
TVariablesAn 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.
Parameters
options
SubscriptionOptions<TVariables, T>Show/hide child attributes
options.context (optional)
DefaultContextContext object to be passed through the link execution chain.
options.errorPolicy (optional)
ErrorPolicySpecifies the ErrorPolicy to be used for this operation
options.fetchPolicy (optional)
FetchPolicySpecifies the FetchPolicy to be used for this subscription.
options.query
DocumentNode | TypedDocumentNode<TData, TVariables>A GraphQL document, often created with gql from the graphql-tag package, that contains a single subscription inside of it.
options.variables (optional)
TVariablesAn 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.
Parameters
options
DataProxy.Query<TVariables, T>Show/hide child attributes
options.id (optional)
stringThe 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.
options.query
DocumentNode | TypedDocumentNode<TData, TVariables>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.
options.variables (optional)
TVariablesAny variables that the GraphQL query may depend on.
optimistic (optional)
booleanSet 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.
Parameters
options
DataProxy.Fragment<TVariables, T>Show/hide child attributes
options.fragment
DocumentNode | TypedDocumentNode<TData, TVariables>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.
options.fragmentName (optional)
stringThe 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.
options.id (optional)
stringThe 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.
options.variables (optional)
TVariablesAny variables that your GraphQL fragments depend on.
optimistic (optional)
booleanSet to true to allow readFragment to return optimistic results. Is false by default.
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.
Parameters
options
DataProxy.WriteQueryOptions<TData, TVariables>Show/hide child attributes
options.broadcast (optional)
booleanWhether to notify query watchers (default: true).
options.data
TDataThe data you will be writing to the store.
options.id (optional)
stringThe 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.
options.overwrite (optional)
booleanWhen true, ignore existing field data rather than merging it with incoming data (default: false).
options.query
DocumentNode | TypedDocumentNode<TData, TVariables>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.
options.variables (optional)
TVariablesAny 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.
Parameters
options
DataProxy.WriteFragmentOptions<TData, TVariables>Show/hide child attributes
options.broadcast (optional)
booleanWhether to notify query watchers (default: true).
options.data
TDataThe data you will be writing to the store.
options.fragment
DocumentNode | TypedDocumentNode<TData, TVariables>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.
options.fragmentName (optional)
stringThe 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.
options.id (optional)
stringThe 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.
options.overwrite (optional)
booleanWhen true, ignore existing field data rather than merging it with incoming data (default: false).
options.variables (optional)
TVariablesAny 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.
Parameters
cb
() => Promise<any>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.
Parameters
cb
() => Promise<any>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.
Parameters
includeStandby (optional)
booleanRefetches 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.
Parameters
options
RefetchQueriesOptions<TCache, TResult>Show/hide child attributes
options.include (optional)
RefetchQueriesIncludeoptions.onQueryUpdated (optional)
OnQueryUpdated<TResult> | nulloptions.optimistic (optional)
booleanoptions.updateCache (optional)
(cache: TCache) => voidGet all currently active ObservableQuery objects, in a Map keyed by query ID strings.
An "active" query is one that has observers and a fetchPolicy other than "standby" or "cache-only".
You can include all ObservableQuery objects (including the inactive ones) by passing "all" instead of "active", or you can include just a subset of active queries by passing an array of query names or DocumentNode objects.
Parameters
include (optional)
RefetchQueriesIncludeTypes
Properties
cache
ApolloCache<TCacheShape>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.
link (optional)
ApolloLinkYou can provide an ApolloLink 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.
uri (optional)
string | UriFunctionThe 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.
connectToDevTools (optional)
booleanIf true, the Apollo Client Devtools browser extension can connect to Apollo Client.
The default value is false in production and true in development (if there is a window object).
defaultOptions (optional)
DefaultOptionsProvide 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 this example object.
name (optional)
stringA 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 (optional)
stringA 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.
assumeImmutableResults (optional)
booleanIf true, Apollo Client will assume results read from the cache are never mutated by application code, which enables substantial performance optimizations.
credentials (optional)
stringdocumentTransform (optional)
DocumentTransformfragmentMatcher (optional)
FragmentMatcherheaders (optional)
Record<string, string>queryDeduplication (optional)
booleanIf 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.
resolvers (optional)
Resolvers | Resolvers[]ssrForceFetchDelay (optional)
numberThe time interval (in milliseconds) before Apollo Client force-fetches queries after a server-side render.
ssrMode (optional)
booleanWhen using Apollo Client for server-side rendering, set this to true so that the getDataFromTree function can work effectively.
typeDefs (optional)
string | string[] | DocumentNode | DocumentNode[]Properties
mutate (optional)
Partial<MutationOptions<any, any, any>>query (optional)
Partial<QueryOptions<any, any>>watchQuery (optional)
Partial<WatchQueryOptions<any, any>>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.