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): ApolloClient<TCacheShape>

(src/core/ApolloClient.ts, line 127)

Takes an ApolloClientOptions parameter that supports the fields listed below.

Returns an initialized ApolloClient object.

Example

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import { ApolloClient, InMemoryCache } from '@apollo/client';
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const cache = new InMemoryCache();
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const client = new ApolloClient({
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  // Provide required constructor fields
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  cache: cache,
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  uri: 'http://localhost:4000/',
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  // Provide some optional constructor fields
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  name: 'react-web-client',
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  version: '1.3',
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  queryDeduplication: false,
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  defaultOptions: {
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    watchQuery: {
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      fetchPolicy: 'cache-and-network',
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    },
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  },
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});

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.
`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.
`assumeImmutableResults` `Boolean`	If `true`, Apollo Client will assume results read from the cache are never mutated by application code, which enables substantial performance optimizations. The default value is `false`.

Example `defaultOptions` object

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

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 286)

Options

Name / Type	Description
`canonizeResults` `boolean`
`context` `DefaultContext`
`errorPolicy` `ErrorPolicy`
`fetchPolicy` `WatchQueryFetchPolicy`
`initialFetchPolicy` `WatchQueryFetchPolicy`
`nextFetchPolicy` `any`
`notifyOnNetworkStatusChange` `boolean`
`partialRefetch` `boolean`
`pollInterval` `number`
`query` `DocumentNode \| TypedDocumentNode`
`refetchWritePolicy` `RefetchWritePolicy`
`returnPartialData` `boolean`
`variables` `TVariables`

query(options): Promise<ApolloQueryResult>

(src/core/ApolloClient.ts, line 314)

Options

Name / Type	Description
`canonizeResults` `boolean`
`context` `DefaultContext`
`errorPolicy` `ErrorPolicy`
`fetchPolicy` `FetchPolicy`
`notifyOnNetworkStatusChange` `boolean`
`partialRefetch` `boolean`
`pollInterval` `number`
`query` `DocumentNode \| TypedDocumentNode`
`returnPartialData` `boolean`
`variables` `TVariables`

mutate(options): Promise<FetchResult>

(src/core/ApolloClient.ts, line 343)

Options

Name / Type	Description
`awaitRefetchQueries` `boolean`
`context` `TContext`
`errorPolicy` `ErrorPolicy`
`fetchPolicy` `MutationFetchPolicy`
`keepRootFields` `boolean`
`mutation` `DocumentNode \| TypedDocumentNode`
`onQueryUpdated` `OnQueryUpdated<any>`
`optimisticResponse` `any`
`refetchQueries` `any`
`update` `MutationUpdaterFunction<TData, TVariables, TContext, TCache>`
`updateQueries` `MutationQueryReducersMap<TData>`
`variables` `TVariables`