Logging into Salient Data uses the GraphQL Resolver RootMutation logIn(),

This resolver is a member of the mutation family.

GraphiQL Mutation

mutation {
  logIn(username: "{username}", password: "{password}") {
    token
    data {
      _id
    }
  }
}

The resulting data is:

{
  "data": {
    "logIn": {
      "token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJfaWQiOiI1YTNmYzk5MWJkMWE2ODBmZDliMTE4ZGEiLCJpYXQiOjE1MTY3NzkxMjYsImV4cCI6MTUxNjg2NTUyNiwiaXNzIjoiZmVhdGhlcnMifQ.pB2qdyns8E-RZWXo5AxtCGqGzkHu4Exq3OwjItn7Z24",
      "data": {
        "_id": "5a3fc991bd1a680fd9b118da"
      }
    }
  }
}

The token is what is used for the Authorization header.

Apollo Client Mutation

Apollo Client requires the mutation be formatted in the following method

{
  mutation: gql`
    mutation logIn($username: String!, $password: String!) {
      logIn(username: $username, password: $password) {
        _id
      }
    }
  `,
  variables: {
    username: form.value.inputUserName,
    password: form.value.inputPassword
  },
}

Apollo Client has several dependencies , which includes the graphql-tag

In the client, the following code would be used.

import { Apollo } from 'apollo-angular';
import gql from 'graphql-tag';

class LogIn { ... }

constructor(
  private apollo: Apollo
) {}

const logIn = {
  mutation: gql`
    mutation logIn($username: String!, $password: String!) {
      logIn(username: $username, password: $password) {
        _id
      }
    }
  `,
  variables: {
    username: form.value.inputUserName,
    password: form.value.inputPassword
  },
};

this.apollo.mutate(logIn).subscribe(console.log);