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',},},});
Options
Name / Type | Description |
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| The URI of the GraphQL endpoint that Apollo Client will communicate with. One of |
| You can provide an Apollo Link instance to serve as Apollo Client's network layer. For more information, see Advanced HTTP networking. One of |
| Required. The cache that Apollo Client should use to store query results locally. The recommended cache is For more information, see Configuring the cache. |
| A custom name (e.g., |
| A custom version that identifies the current version of this particular client (e.g., 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. |
| When using Apollo Client for server-side rendering, set this to The default value is |
| The time interval (in milliseconds) before Apollo Client force-fetches queries after a server-side render. The default value is |
| If The default value is |
| If The default value is |
| Provide this object to set application-wide default values for options you can provide to the See the example object below. |
| If The default value is |
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.
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.
Options
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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
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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
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This subscribes to a graphql subscription according to the options specified and returns an Observable which either emits received data or an error.
Options
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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 |
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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
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Options
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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
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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
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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
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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
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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
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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
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Get 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.
Arguments
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Types
Properties
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Properties
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