Type Alias ClientResolver

Example

import { ApolloClient, ApolloLink, InMemoryCache } from '@apollo/client'
import { HttpLink } from '@apollo/client/link/http'
import { GraphQLWsLink } from '@apollo/client/link/subscriptions'
import { OperationTypeNode } from 'graphql'
import { createSharedClient } from 'graphql-shared-ws'
import { setupRestartSubscription } from 'apollo-shared-ws'

// GraphQL API endpoint served over wss.
const apiSharedClient = createSharedClient({ url: 'wss://api.example.com/graphql' })

// GraphQL performance reporting endpoint served over wss.
const perfSharedClient = createSharedClient({ url: 'wss://perf.example.com/graphql' })

// Return the SharedClient associated with the GraphQLWsLink that will handle
// the operation.
const clientResolver: ClientResolver = (operation) => {
  if (operation.operationType !== OperationTypeNode.SUBSCRIPTION) return undefined

  if (operation.operationName?.startsWith('api')) {
    return apiSharedClient
  }

  return perfSharedClient
}

const apiLink = new GraphQLWsLink(apiSharedClient)
const perfLink = new GraphQLWsLink(perfSharedClient)

const wsLink = ApolloLink.split(
  ({ operationName }) => Boolean(operationName?.startsWith('api')),
  apiLink,
  perfLink
)

const httpLink = new HttpLink({ uri: 'https://example.com/graphql' })

const link = ApolloLink.split(
  ({ operationType }) => Boolean(operationType === OperationTypeNode.SUBSCRIPTION),
  wsLink,
  httpLink
)

const client = new ApolloClient({
  link,
  cache: new InMemoryCache(),
})

setupRestartSubscription(client, {
  sharedClientResolver: clientResolver,
})
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