Nest could not find GraphQLModule element - graphql

I'm trying to write the e2e test for my backend app (nestjs, grpahql, mongodb).
This is my test:
import { INestApplication } from '#nestjs/common';
import { GraphQLModule } from '#nestjs/graphql';
import { Test, TestingModule } from '#nestjs/testing';
import {
ApolloServerTestClient,
createTestClient,
} from 'apollo-server-testing';
import gql from 'graphql-tag';
import { UserModule } from '../src/user/user.module';
import { MongooseModule } from '#nestjs/mongoose';
import config from '../src/environments/environment';
describe('User', () => {
let app: INestApplication;
let apolloClient: ApolloServerTestClient;
beforeEach(async () => {
const moduleFixture: TestingModule = await Test.createTestingModule({
imports: [UserModule, MongooseModule.forRoot(config.mongoURI)],
}).compile();
app = moduleFixture.createNestApplication();
await app.init();
const module: GraphQLModule = moduleFixture.get<GraphQLModule>(
GraphQLModule,
);
apolloClient = createTestClient((module as any).apolloServer);
});
it('should get users', async () => {
const { query } = apolloClient;
const result: any = await query({
query: gql`
query {
getUsers {
_id
name
}
}
`,
variables: {},
});
console.log(result);
});
});
I face this error:
Nest could not find GraphQLModule element (this provider does not exist in the current context)
Could someone share a working example or point me what is wrong?

It looks like GraphQLModule is not imported in the scope of your TestModule. If so, the context will never be able to provide it using get().
Also, this might not help you but this is what we do in our projects:
beforeAll(async () => {
const TCP_PORT = 4242;
const testingModule = await Test.createTestingModule({
imports: [AppModule],
}).compile();
gqlClient = new ApolloClient({
uri: `http://localhost:${TCP_PORT}/graphql`,
fetch: fetch as any,
cache: new InMemoryCache({
addTypename: false,
}),
});
app = testingModule.createNestApplication();
await app.listen(TCP_PORT);
});
I did not add all the imports but here are the most relevant:
import ApolloClient, { gql, InMemoryCache } from 'apollo-boost';
import fetch from 'node-fetch';
I assume you know the other ones and/or don't need them

Related

Apollo GraphQL react client: subscription

I was trying to make a little demo with GraphQL subscriptions and GraphQL Apollo client.
I already have my GraphQL API, but when I try to use Apollo client, it looks like it doesn't complete the websocket subscribe step:
import React from 'react';
import ReactDOM from 'react-dom/client';
import './index.css';
import { ApolloClient, InMemoryCache, ApolloProvider, gql, useQuery } from '#apollo/client';
import { split, HttpLink } from '#apollo/client';
import { getMainDefinition } from '#apollo/client/utilities';
import { GraphQLWsLink } from '#apollo/client/link/subscriptions';
import { createClient } from 'graphql-ws';
import { useSubscription } from '#apollo/react-hooks'
import reportWebVitals from './reportWebVitals';
const httpLink = new HttpLink({
uri: 'https://mygraphql.api'
});
const wsLink = new GraphQLWsLink(createClient({
url: 'wss://mygraphql.api',
options: {
reconnect: true
}
}));
const splitLink = split(
({ query }) => {
const definition = getMainDefinition(query);
return (
definition.kind === 'OperationDefinition' &&
definition.operation === 'subscription'
);
},
wsLink,
httpLink,
);
const client = new ApolloClient({
link: splitLink,
cache: new InMemoryCache(),
fetchOptions: {
mode: 'no-cors',
}
});
const FAMILIES_SUBSCRIPTION = gql`
subscription{
onFamilyCreated {
id
name
}
}
`;
function LastFamily() {
const { loading, error, data } = useSubscription(FAMILIES_SUBSCRIPTION, {
variables: { },
onData: data => console.log('new data', data)
});
if (loading) return <div>Loading...</div>;
if (error) return <div>Error!</div>;
console.log(data);
const family = data.onFamilyCreated[0];
return (
<div>
<h1>{family.name}</h1>
</div>
);
}
const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(
(<ApolloProvider client={client}>
<div>
<LastFamily />
</div>
</ApolloProvider>));
reportWebVitals();
According to graphql-transport-ws, to accomplish a success call, it should call connection_init and subscribe message. But when I open Dev Tools, it only sends "connection_init"
I'm expecting this output:
What step should I add to accomplish a successful call using graphql-transport-ws?
P.s. I'm not a React Developer, just be kind.
The solutions I'm putting up are based on #apollo/server v.4, with expressMiddleware and mongodb/mongoose on the backend and subscribeToMore with updateQuery on the client-side instead of useSubscription hook. In light of my observations, I believe there may be some issues with your backend code that require refactoring. The transport library graphql-transport-ws has been deprecated and advise to use graphql-ws. The following setup also applies as of 12.2022.
Subscription on the backend
Install the following dependencies.
$ npm i #apollo/server #graphql-tools/schema graphql-subscriptions graphql-ws ws cors body-parser mongoose graphql express
Set up the db models, I will refer to mongodb using mongoose and it might look like this one e.g.
import mongoose from 'mongoose'
const Schema = mongoose.Schema
const model = mongoose.model
const FamilySchema = new Schema({
name: {
type: String,
unique: true, //optional
trim: true,
}
})
FamilySchema.virtual('id').get(function () {
return this._id.toHexString()
})
FamilySchema.set('toJSON', {
virtuals: true,
transform: (document, retObj) => {
delete retObj.__v
},
})
const FamilyModel = model('FamilyModel', FamilySchema)
export default FamilyModel
Setup schema types & resolvers; it might look like this one e.g.
// typeDefs.js
const typeDefs = `#graphql
type Family {
id: ID!
name: String!
}
type Query {
families: [Family]!
family(familyId: ID!): Family!
}
type Mutation {
createFamily(name: String): Family
}
type Subscription {
familyCreated: Family
}
`
// resolvers.js
import { PubSub } from 'graphql-subscriptions'
import mongoose from 'mongoose'
import { GraphQLError } from 'graphql'
import FamilyModel from '../models/Family.js'
const pubsub = new PubSub()
const Family = FamilyModel
const resolvers = {
Query: {
families: async () => {
try {
const families = await Family.find({})
return families
} catch (error) {
console.error(error.message)
}
},
family: async (parent, args) => {
const family = await Family.findById(args.familyId)
return family
},
Mutation: {
createFamily: async (_, args) => {
const family = new Family({ ...args })
try {
const savedFamily = await family.save()
const createdFamily = {
id: savedFamily.id,
name: savedFamily.name
}
// resolvers for backend family subscription with object iterator FAMILY_ADDED
pubsub.publish('FAMILY_CREATED', { familyCreated: createdFamily })
return family
} catch (error) {
console.error(error.message)
}
}
},
Subscription: {
familyCreated: {
subscribe: () => pubsub.asyncIterator('FAMILY_CREATED'),
}
},
Family: {
id: async (parent, args, contextValue, info) => {
return parent.id
},
name: async (parent) => {
return parent.name
}
}
}
export default resolvers
At the main entry server file (e.g. index.js) the code might look like this one e.g.
import dotenv from 'dotenv'
import { ApolloServer } from '#apollo/server'
import { expressMiddleware } from '#apollo/server/express4'
import { ApolloServerPluginDrainHttpServer } from '#apollo/server/plugin/drainHttpServer'
import { makeExecutableSchema } from '#graphql-tools/schema'
import { WebSocketServer } from 'ws'
import { useServer } from 'graphql-ws/lib/use/ws'
import express from 'express'
import http from 'http'
import cors from 'cors'
import bodyParser from 'body-parser'
import typeDefs from './schema/tpeDefs.js'
import resolvers from './schema/resolvers.js'
import mongoose from 'mongoose'
dotenv.config()
...
mongoose.set('strictQuery', false)
let db_uri
if (process.env.NODE_ENV === 'development') {
db_uri = process.env.MONGO_DEV
}
mongoose.connect(db_uri).then(
() => {
console.log('Database connected')
},
(err) => {
console.log(err)
}
)
const startGraphQLServer = async () => {
const app = express()
const httpServer = http.createServer(app)
const schema = makeExecutableSchema({ typeDefs, resolvers })
const wsServer = new WebSocketServer({
server: httpServer,
path: '/',
})
const serverCleanup = useServer({ schema }, wsServer)
const server = new ApolloServer({
schema,
plugins: [
ApolloServerPluginDrainHttpServer({ httpServer }),
{
async serverWillStart() {
return {
async drainServer() {
await serverCleanup.dispose()
},
}
},
},
],
})
await server.start()
app.use(
'/',
cors(),
bodyParser.json(),
expressMiddleware(server)
)
const PORT = 4000
httpServer.listen(PORT, () =>
console.log(`Server is now running on http://localhost:${PORT}`)
)
}
startGraphQLServer()
Subscription on the CRA frontend
Install the following dependencies.
$ npm i #apollo/client graphql graphql-ws
General connection setup e.g.
// src/client.js
import { ApolloClient, HttpLink, InMemoryCache, split } from '#apollo/client'
import { getMainDefinition } from '#apollo/client/utilities'
import { defaultOptions } from './graphql/defaultOptions'
import { GraphQLWsLink } from '#apollo/client/link/subscriptions'
import { createClient } from 'graphql-ws'
...
const baseUri = process.env.REACT_APP_BASE_URI // for the client
const wsBaseUri = process.env.REACT_APP_WS_BASE_URI // for the backend as websocket
const httpLink = new HttpLink({
uri: baseUri,
})
const wsLink = new GraphQLWsLink(
createClient({
url: wsBaseUri
})
)
const splitLink = split(
({ query }) => {
const definition = getMainDefinition(query)
return (
definition.kind === 'OperationDefinition' &&
definition.operation === 'subscription'
)
},
wsLink,
httpLink
)
const client = new ApolloClient({
cache: new InMemoryCache(),
link: splitLink,
})
export default client
// src/index.js
import React from 'react'
import ReactDOM from 'react-dom/client'
import client from './client'
import { ApolloProvider } from '#apollo/client'
import App from './App'
const root = ReactDOM.createRoot(document.getElementById('root'))
root.render(
<React.StrictMode>
<ApolloProvider client={client}>
<App />
</ApolloProvider>
</React.StrictMode>
)
Define the operations types for the client: queries, mutation & subscription e.g.
// src/graphql.js
import { gql } from '#apollo/client'
// Queries
export const FAMILIES = gql`
query Families {
families {
id
name
}
}
`
export const FAMILY = gql`
query Family($familyId: ID) {
family {
id
name
}
}
`
// Mutation
export const CREATE_FAMILY = gql`
mutation createFamily($name: String!) {
createFamily(name: $name) {
id
name
}
}
`
// Subscription
export const FAMILY_SUBSCRIPTION = gql`
subscription {
familyCreated {
id
name
}
}
Components, it might look like this one e.g.
Apollo's useQuery hook provides us with access to a function called subscribeToMore. This function can be destructured and used to act on new data that comes in via subscription. This has the result of rendering our app real-time.
The subscribeToMore function utilizes a single object as an argument. This object requires configuration to listen for and respond to subscriptions.
At the very least, we must pass a subscription document to the document key in this object. This is a GraphQL document in which we define our subscription.
We can a updateQuery field that can be used to update the cache, similar to how we would do in a mutation.
// src/components/CreateFamilyForm.js
import { useMutation } from '#apollo/client'
import { CREATE_FAMILY, FAMILIES } from '../graphql'
...
const [createFamily, { error, loading, data }] = useMutation(CREATE_FAMILY, {
refetchQueries: [{ query: FAMILIES }], // be sure to refetchQueries after mutation
})
...
// src/components/FamilyList.js
import React, { useEffect, useState } from 'react'
import { useQuery } from '#apollo/client'
import { Families, FAMILY_SUBSCRIPTION } from '../graphql'
const { cloneDeep, orderBy } = pkg
...
export const FamilyList = () => {
const [families, setFamilies] = useState([])
const { loading, error, data, subscribeToMore } = useQuery(Families)
...
useEffect(() => {
if (data?.families) {
setFamilies(cloneDeep(data?.families)) // if you're using lodash but it can be also setFamilies(data?.families)
}
}, [data?.families])
useEffect(() => {
subscribeToMore({
document: FAMILY_SUBSCRIPTION,
updateQuery: (prev, { subscriptionData }) => {
if (!subscriptionData.data) return prev
const newFamily = subscriptionData.data.familyCreated
if (!prev.families.find((family) => family.id === newFamily.id)) {
return Object.assign({}, prev.families, {
families: [...prev.families, newFamily],
})
} else {
return prev
}
},
})
}, [subscribeToMore])
const sorted = orderBy(families, ['names'], ['desc']) // optional; order/sort the list
...
console.log(sorted)
// map the sorted on the return statement
return(...)
END. Hard-coding some of the default resolvers are useful for ensuring that the value that you expect will returned while avoiding the return of null values. Perhaps not in every case, but for fields that refer to other models or schema.
Happy coding!

Apollo Subscription with Gatsby Setup

below is my setup of Gatsby SSR with Apollo for those looking for a solution on how to set them up. Hope it helps those looking online for a solution on how to set up Gatsby with Apollo
Credits: [https://github.com/apollographql/subscriptions-transport-ws/issues/333]
I am not sure at the moment if my onError variable is placed correctly. I will look it up
Nonetheless, subscription with gatsby client-side routes is working fine with this setup
client.js // to be imported into ApolloProvider
import ApolloClient from 'apollo-client'
// import * as ws from 'ws'
// import { createHttpLink } from 'apollo-link-http'
import { split } from 'apollo-link'
// import { setContext } from 'apollo-link-context'
import { onError } from 'apollo-link-error'
import { HttpLink } from 'apollo-link-http'
import { WebSocketLink } from 'apollo-link-ws'
// import fetch from 'isomorphic-fetch' // Comment out this line results in an error ...
import 'isomorphic-fetch'
import { InMemoryCache } from 'apollo-cache-inmemory'
import { getMainDefinition } from 'apollo-utilities'
const HTTP_URI = `http://localhost:4000/graphql`
const WS_URI = `ws://localhost:4000/graphql`
const httplink = new HttpLink({
uri: HTTP_URI,
// credentials: 'same-origin',
// fetch,
})
const wsLink = process.browser
? new WebSocketLink({
// if you instantiate in the server, the error will be thrown
uri: WS_URI,
options: {
reconnect: true,
},
})
: null
const errorLink = onError(({ networkError, graphQLErrors }) => {
if (graphQLErrors) {
graphQLErrors.map(({ message, locations, path }) =>
console.log(
`[GraphQL error]: Message: ${message}, Location: ${locations}, Path: ${path}`
)
)
}
if (networkError) console.log(`[Network error]: ${networkError}`)
})
const link = process.browser
? split(
//only create the split in the browser
// split based on operation type
({ query }) => {
const { kind, operation } = getMainDefinition(query)
return kind === 'OperationDefinition' && operation === 'subscription'
},
wsLink,
httplink,
errorLink
)
: httplink
export const client = new ApolloClient({
link,
cache: new InMemoryCache(),
})
graphql/subscriptions.js
import gql from 'graphql-tag'
const BOOK_ADDED_SUBSCRIPTION = gql`
subscription {
bookAdded {
_id
title
author
}
}
`
export { BOOK_ADDED_SUBSCRIPTION }

How to do graphql and graphql subscriptions with svelte

To do graphql queries and mutations ive had success with both fetch and svelte-apollo (see https://github.com/timhall/svelte-apollo)
I like the fech approach for its simplicity.
Svelte-apollo features subscriptions and I will try to get it to work.
But are there alternatives?
How do you consume graphql subscriptions with svelte?
Heres my solution, using Apollo:
import { ApolloClient } from 'apollo-client';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { HttpLink } from 'apollo-link-http';
import { WebSocketLink } from 'apollo-link-ws';
import { split } from 'apollo-link';
import { getMainDefinition } from 'apollo-utilities';
const httpLink = new HttpLink({
uri: 'http://localhost:3000/graphql'
});
const wsLink = new WebSocketLink({
uri: `ws://localhost:3000/subscriptions`,
options: {
reconnect: true
}
});
const link = split(
// split based on operation type
({ query }) => {
const definition = getMainDefinition(query);
return (
definition.kind === 'OperationDefinition' &&
definition.operation === 'subscription'
);
},
wsLink,
httpLink,
);
const client = new ApolloClient({
link,
cache: new InMemoryCache()
});
After all that, you have your client set up. Next,
import gql from 'graphql-tag';
client.subscribe({
query: gql`subscription { whatever }`
}).subscribe(result => console.log(result.data);
I'm using urql's svelte bindings. The documentation also shows how to use the bindings with subscriptions.

Access to Apollo server for NestJS GraphQL test

A standard way to test an Apollo GraphQL server is to use the Apollo test client.
The createTestClient method requires a server argument.
In a NestJS/TypeGraphQL application, what's the appropriate way to access the Apollo server that's created by GraphQLModule from inside a (Jest) test?
const moduleFixture = await Test.createTestingModule({
imports: [ApplicationModule],
}).compile()
const app = await moduleFixture.createNestApplication(new ExpressAdapter(express)).init()
const module: GraphQLModule = moduleFixture.get<GraphQLModule>(GraphQLModule)
const apolloClient = createTestClient((module as any).apolloServer)
this is what i do
This code worked for me. Thanks to JustMe
import { Test, TestingModule } from '#nestjs/testing';
import { INestApplication } from '#nestjs/common';
import { createTestClient, TestQuery } from 'apollo-server-integration-testing';
import { AppModule } from './../src/app.module';
import { GraphQLModule } from '#nestjs/graphql';
describe('AppController (e2e)', () => {
let app: INestApplication;
// let mutateTest: TestQuery;
let correctQueryTest: TestQuery;
let wrongQueryTest: TestQuery;
beforeEach(async () => {
const moduleFixture: TestingModule = await Test.createTestingModule({
imports: [AppModule],
}).compile();
app = moduleFixture.createNestApplication();
await app.init();
const module: GraphQLModule =
moduleFixture.get<GraphQLModule>(GraphQLModule);
const { query: correctQuery } = createTestClient({
apolloServer: (module as any).apolloServer,
extendMockRequest: {
headers: {
token:
'iIsInR5cCI6IkpXVCJ9.eyJfaWQiOiI2MWFiNmY0MjQ3YjEyYWNiNzQyYmQwYmYiLCJyb2xlIjoibWFuYWdlciIsImVtYWlsIjoibGVuYUBtYWlsLmNvbSIsInBhc3N3b3JkIjoiZTEwYWRjMzk0OWJhNTlhYmJlNTZlMDU3ZjIwZjg4M2UiLCJ1c2VybmFtZSI6ImxlbmEgZG9lIiwiY3JlYXRlZEF0IjoiMjAyMS0xMi0wNFQxMzozODoxMC4xMzZaIiwidXBkYXRlZEF0IjoiMjAyMS0xMi0wNFQxMzozODoxMC4xMzZaIiwiX192IjowLCJpYXQiOjE2Mzg2NTE4MjMsImV4cCI6MTYzODY1MTg4M30.d6SCh4x6Wwpj16UWf4ca-PbFCo1FQm_bLelp8kscG8U',
},
},
});
const { query: wrongQuery } = createTestClient({
apolloServer: (module as any).apolloServer,
});
// mutateTest = mutate;
correctQueryTest = correctQuery;
wrongQueryTest = wrongQuery;
});
it('/ Correct', async () => {
const result = await correctQueryTest(`
query FILTER_JOBS{
filterJobs(status: DONE) {
title,
status,
description,
lat,
long,
employees,
images,
assignedBy {
username,
email
}
}
}
`);
console.log(result);
});
it('/ Wrong', async () => {
const result = await wrongQueryTest(`
query FILTER_JOBS{
filterJobs(status: DONE) {
title,
status,
description,
lat,
long,
employees,
images,
assignedBy {
username,
email
}
}
}
`);
console.log(result);
});
});
After searching I ended using this:
import { getApolloServer } from '#nestjs/apollo';
import { INestApplication, ValidationPipe } from '#nestjs/common';
import { Test, TestingModule } from '#nestjs/testing';
import { ApolloServerBase, gql } from 'apollo-server-core';
import { AppModule } from './../src/app.module';
describe('AppController (e2e)', () => {
let app: INestApplication;
let apolloServer: ApolloServerBase<any>;
beforeAll(async () => {
const moduleFixture: TestingModule = await Test.createTestingModule({
imports: [AppModule],
}).compile();
app = moduleFixture.createNestApplication();
app.useGlobalPipes(new ValidationPipe());
await app.init();
apolloServer = getApolloServer(app);
});
afterAll(async () => {
await app.close();
});
it('signUp', async () => {
const signUpInput = gql`
mutation Mutation($signUpInput: SignUpInput!) {
signup(signUpInput: $signUpInput) {
access
refresh
}
}
`;
const signUpResponse = await apolloServer.executeOperation({
query: signUpInput,
variables: {
signUpInput: {
name: 'John',
lastName: 'Doe',
email: 'test#gmail.com',
password: 'password',
},
},
});
expect(signUpResponse.data).toBeDefined();
});
});
This PR https://github.com/nestjs/graphql/pull/1104 enables you to write tests using apollo-server-testing.

Apollo client link state "Missing field in {}" when writing to cache?

Im using Apollo Client, Graphcool and React. I have a working login form but I need the UI to update when the user is logged in, and I need this to happen in different components.
It seems apollo-link-state is the solution for this. My code below seems to work but Im getting this error:
Missing field CurrentUserIsLoggedIn in {} in writeToStore.js
My Apollo Client setup:
import React from 'react';
import ReactDOM from 'react-dom';
// Apollo
import { ApolloProvider } from 'react-apollo';
import { ApolloClient } from 'apollo-client';
import { HttpLink } from 'apollo-link-http';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloLink, split } from 'apollo-link';
import { withClientState } from 'apollo-link-state';
import { WebSocketLink } from 'apollo-link-ws';
import { getMainDefinition } from 'apollo-utilities';
// Components
import LoginTest from './components/App/LoginTest';
const wsLink = new WebSocketLink({
uri: `wss://subscriptions.graph.cool/v1/XXX`,
options: {
reconnect: true,
},
});
// __SIMPLE_API_ENDPOINT__ looks like: 'https://api.graph.cool/simple/v1/__SERVICE_ID__'
const httpLink = new HttpLink({
uri: 'https://api.graph.cool/simple/v1/XXX',
});
// auth
const middlewareAuthLink = new ApolloLink((operation, forward) => {
const token = localStorage.getItem('auth-token');
const authorizationHeader = token ? `Bearer ${token}` : null;
operation.setContext({
headers: {
authorization: authorizationHeader,
},
});
return forward(operation);
});
const cache = new InMemoryCache();
const defaultState = {
CurrentUserIsLoggedIn: {
__typename: 'CurrentUserIsLoggedIn',
value: false,
},
};
const stateLink = withClientState({
cache,
defaults: defaultState,
resolvers: {
Mutation: {
CurrentUserIsLoggedIn: (_, args) => {
const data = {
CurrentUserIsLoggedIn: {
__typename: 'CurrentUserIsLoggedIn',
value: args.value,
},
};
cache.writeData({ data });
},
},
},
});
const client = new ApolloClient({
cache,
link: ApolloLink.from([
stateLink,
middlewareAuthLink,
split(
// split based on operation type
({ query }) => {
const { kind, operation } = getMainDefinition(query);
return kind === 'OperationDefinition' && operation === 'subscription';
},
wsLink,
httpLink,
),
]),
});
ReactDOM.render(
<ApolloProvider client={client}>
<LoginTest />
</ApolloProvider>,
document.getElementById('root'),
);
LoginTest.js:
import React from 'react';
import { graphql, compose } from 'react-apollo';
import gql from 'graphql-tag';
import App from './App';
const LoginTest = props => {
if (props.LoginServerQuery.loading) return <p>Loading...</p>;
// If the server tells us the user is logged in
if (props.LoginServerQuery.loggedInUser) {
// Then set the local logged in state to true
props.CurrentUserIsLoggedInMutation({
variables: {
value: true,
},
});
}
return <App />;
};
const CurrentUserIsLoggedInMutation = gql`
mutation CurrentUserIsLoggedInMutation($value: Boolean) {
CurrentUserIsLoggedIn(value: $value) #client {
value
}
}
`;
const LoginServerQuery = gql`
query LoginServerQuery {
loggedInUser {
id
}
}
`;
const LoginTestQuery = compose(
graphql(LoginServerQuery, { name: 'LoginServerQuery' }),
graphql(CurrentUserIsLoggedInMutation, {
name: 'CurrentUserIsLoggedInMutation',
}),
)(LoginTest);
export default LoginTestQuery;
At the moment, apollo-link-state requires you to return any result in your resolver function. It can be null too. This might be changed in the future.
const stateLink = withClientState({
cache,
defaults: defaultState,
resolvers: {
Mutation: {
CurrentUserIsLoggedIn: (_, args) => {
const data = {
CurrentUserIsLoggedIn: {
__typename: 'CurrentUserIsLoggedIn',
value: args.value,
},
};
cache.writeData({ data });
return data;
},
},
},
try adding a return statement in your mutation. Similar problem occured here with different function: apollo-link-state cache.writedata results in Missing field warning

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