apollo graphql mutation - Unexpected end of JSON input

Question

I'm making a simple test with @apollo/react-hooks, and I'm getting this error:

ApolloError.ts:46 Uncaught (in promise) Error: Network error: Unexpected end of JSON input
    at new ApolloError (ApolloError.ts:46)
    at Object.error (QueryManager.ts:255)
    at notifySubscription (Observable.js:140)
    at onNotify (Observable.js:179)
    at SubscriptionObserver.error (Observable.js:240)
    at observables.ts:15
    at Set.forEach (<anonymous>)
    at Object.error (observables.ts:15)
    at notifySubscription (Observable.js:140)
    at onNotify (Observable.js:179)
    at SubscriptionObserver.error (Observable.js:240)
    at Object.error (index.ts:81)
    at notifySubscription (Observable.js:140)
    at onNotify (Observable.js:179)
    at SubscriptionObserver.error (Observable.js:240)
    at httpLink.ts:184

When I try to use a mutation like this:

import React from 'react';
import { Button } from 'antd';
import { gql } from 'apollo-boost';
import { useMutation } from '@apollo/react-hooks';

const LOGIN = gql`
  mutation authentication($accessToken: String!) {
    login(accessToken: $accessToken) {
      id
      name
      email
      groups
    }
  }
`;

function Authenticating() {
   const [login] = useMutation(LOGIN);

   function handleClick() {
      const variables = { variables: { accessToken: 'access_token_here' } };

      azureLogin(variables).then(data => {
          console.log(data); 
      }).catch(err => {
          console.log(err)
      });
   }

   return (
    <Button onClick={handleClick}>Test</Button>
  );
}

export default Authenticating;

My Apollo client looks like this:

import ApolloClient from 'apollo-boost';

const client = new ApolloClient({
  uri: <graphql_server>,
  fetchOptions: {
    mode: 'no-cors',
  },
  headers: {
    'Content-Type': 'application/json',
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Credentials': true,
  },
  fetch,
});

export default client;

And the Authenticating component is wrapped by an ApolloProvider.

import React from 'react';
import { ApolloProvider } from '@apollo/react-hooks';
import Authenticating from './Authenticating';
import apolloClient from './apolloClient';

const App = () => {
   <ApolloProvider client={apolloClient}>
      <Authenticating/>
   </ApolloProvider>
}

export default App;

I have no clue why I'm getting this error.

Answer 1

There is nothing wrong with the code, it was the backend that didnt have the CORS configuration.

It's a ruby server, and the rack-cors wasn't configurated.

I also changed the apollo client to this, after the backend was fixed:

import ApolloClient from 'apollo-boost';

const client = new ApolloClient({
  uri: <graphql_server>,
  headers: {
    'Content-Type': 'application/json',
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Credentials': true,
  },
  fetch,
});

export default client;

Removed the fetchOptions mode: 'no-cors':

fetchOptions: {
   mode: 'no-cors',
}