npm install --save vue@2.6.6 vue-template-compiler@2.6.6 vue-server-renderer@2.6.6

npm install --save @nuxtjs/apollo

yarn add @nuxtjs/apollo

// nuxt.config.js

export default {
  modules: [
    '@nuxtjs/apollo',
  ],

  apollo: {
    clientConfigs: {
      default: {
        httpEndpoint: 'https://127.0.0.1:4000',
      }
    }
  }
}

npm install --save graphql-tag

yarn add graphql-tag

declare module '*.gql' {
  import { DocumentNode } from 'graphql'

  const content: DocumentNode
  export default content
}

declare module '*.graphql' {
  import { DocumentNode } from 'graphql'

  const content: DocumentNode
  export default content
}

{
  // Add apollo module
  modules: ['@nuxtjs/apollo'],

  apollo: {
    // Sets up the apollo client endpoints
    clientConfigs: {
      // recommended: use a file to declare the client configuration (see below for example)
      default: '~/plugins/my-alternative-apollo-config.js',

      // you can setup multiple clients with arbitrary names
      alternativeClient: {
        // required
        httpEndpoint: 'https://127.0.0.1:4000',

        // override HTTP endpoint in browser only
        browserHttpEndpoint: '/graphql',

        // See https://www.apollographql.com/docs/link/links/http.html#options
        httpLinkOptions: {
          credentials: 'same-origin'
        },

        // You can use `wss` for secure connection (recommended in production)
        // Use `null` to disable subscriptions
        wsEndpoint: 'ws://127.0.0.1:4000',

        // LocalStorage token
        tokenName: 'apollo-token',

        // Enable Automatic Query persisting with Apollo Engine
        persisting: false,

        // Use websockets for everything (no HTTP)
        // You need to pass a `wsEndpoint` for this to work
        websocketsOnly: false
      },
    },
    
    /**
     * default 'apollo' definition
     */
    defaultOptions: {
      // See 'apollo' definition
      // For example: default query options
      $query: {
        loadingKey: 'loading',
        fetchPolicy: 'cache-and-network',
      },
    },
    
    // setup a global query loader observer (see below for example)
    watchLoading: '~/plugins/apollo-watch-loading-handler.js',
    
    // setup a global error handler (see below for example)
    errorHandler: '~/plugins/apollo-error-handler.js',

    // Sets the authentication type for any authorized request.
    authenticationType: 'Bearer', 

    // Token name for the cookie which will be set in case of authentication
    tokenName: 'apollo-token',

    // [deprecated] Enable the graphql-tag/loader to parse *.gql/*.graphql files
    includeNodeModules: true,

    // Cookie parameters used to store authentication token
    cookieAttributes: {
      /**
        * Define when the cookie will be removed. Value can be a Number
        * which will be interpreted as days from time of creation or a
        * Date instance. If omitted, the cookie becomes a session cookie.
        */
      expires: 7,

      /**
        * Define the path where the cookie is available. Defaults to '/'
        */
      path: '/',

      /**
        * Define the domain where the cookie is available. Defaults to
        * the domain of the page where the cookie was created.
        */
      domain: 'example.com',

      /**
        * A Boolean indicating if the cookie transmission requires a
        * secure protocol (https). Defaults to false.
        */
      secure: false,
    },
  }
}

// ~/plugins/my-alternative-apollo-config.js

export default (context) => {
  return {
    httpEndpoint: 'https://127.0.0.1:4000/graphql-alt',

    /*
     * For permanent authentication provide `getAuth` function.
     * The string returned will be used in all requests as authorization header
     */
    getAuth: () => 'Bearer my-static-token',
  }
}

// ~/plugins/apollo-watch-loading-handler.js

export default (isLoading, countModifier, nuxtContext) => {
  loading += countModifier
  console.log('Global loading', loading, countModifier)
}

// ~/plugins/apollo-error-handler.js

export default ({ graphQLErrors, networkError, operation, forward }, nuxtContext) => {
  console.log('Global error handler')
  console.log(graphQLErrors, networkError, operation, forward)
}

 // set your graphql-token
 this.$apolloHelpers.onLogin(token /* if not default you can pass in client as second argument, you can set custom cookies attributes object as the third argument, and you can skip reset store as the fourth argument */)
 // unset your graphql-token
 this.$apolloHelpers.onLogout(/* if not default you can pass in client as first argument, and you can skip reset store as the second argument */)
 // get your current token (we persist token in a cookie)
 this.$apolloHelpers.getToken(/* you can provide named tokenName if not 'apollo-token' */)

// ~/components/my-component.js

export default {
  methods: {
    async onSubmit () {
      const credentials = this.credentials
      try {
          const res = await this.$apollo.mutate({
              mutation: authenticateUserGql,
              variables: credentials
          }).then(({data}) => data && data.authenticateUser)
          await this.$apolloHelpers.onLogin(res.token)
      } catch (e) {
          console.error(e)
      }
    },
  }
}

// ~/components/my-component.js

export default {
  methods: {
    async onLogout () {
      await this.$apolloHelpers.onLogout()
    },
  }
}

// ~/middleware/isAuth.js

export default ({app, error}) => {
  const hasToken = !!app.$apolloHelpers.getToken()
  if (!hasToken) {
    error({
      errorCode:503, 
      message:'You are not allowed to see this'
    })
  }
}

// ~/store/my-store.js

export default {
  actions: {
    foo (store, payload) {
      let client = this.app.apolloProvider.defaultClient
    }
  }
}

// ~/components/my-component.js

export default {
  asyncData (context) {
    let client = context.app.apolloProvider.defaultClient
  }
}

export default {
  nuxtServerInit (store, context) {
    let client = context.app.apolloProvider.defaultClient
  }
}

// ~/components/my-component.js

export default {
  methods: {
    foo () {
      // receive the associated Apollo client 
      const client = this.$apollo.getClient()

      // most likely you would call mutations like following:
      this.$apollo.mutate({mutation, variables})
      
      // but you could also call queries like this:
      this.$apollo.query({query, variables})
        .then(({ data }) => {
          // do what you want with data
        })
    }
  }
}

// nuxt.config.js

export default {
  apollo: {
    foo: {
      query: fooGql,
      variables () {
        return {
          myVar: this.myVar
        }
      }
    }
  }
}

// nuxt.config.js

export default {
  apollo: {
    clientConfigs: {
      default: '~/apollo/client-configs/default.js'
    },
    includeNodeModules: true
  }
}

// nuxt.config.js

export default {
  apollo: {
    clientConfigs: {
      default:{
        httpEndpoint: YOUR_ENDPOINT,
        wsEndpoint: YOUR_WS_ENDPOINT
      }
    }
  }
}

# cat .env
HTTP_ENDPOINT=https://your-endpoint
WS_ENDPOINT=wss://your-endpoint

mutation authenticateUser($email:String!,$password:String!){
    authenticateUser(email: $email, password: $password) {
        token
        id
    }
}

npm install
npm run dev