shrirambalakrishnan

const { rule, shield } = require('graphql-shield')

// Rules
const isUser = rule({ cache: 'contextual' })(
  async (parent, args, ctx, info) => {
    let isUser = ctx.user.roles.includes('USER');
    console.log(`isUser = ${isUser}`);
    return isUser;
  }
)

shrirambalakrishnan

const { AuthDirective } = require("./src/directives/auth")

// The GraphQL schema
const typeDefs = gql`
  directive @auth(
    requires: Role = ADMIN
  ) on FIELD_DEFINITION | OBJECT
  enum Role {
    ADMIN
    REVIEWER

shrirambalakrishnan

const { SchemaDirectiveVisitor } = require("apollo-server");
const { defaultFieldResolver } = require("graphql");

class AuthDirective extends SchemaDirectiveVisitor {
  visitObject(type) {
    this.ensureFieldsWrapped(type);
    type._requiredAuthRole = this.args.requires;
  }
  // Visitor methods for nested types like fields and arguments
  // also receive a details object that provides information about

shrirambalakrishnan

const typeDefs = gql`
  input PostInputType {
    id: Int!
    title: String!
    description: String
  }
  type CommentType {
    id: Int!
    comment: String!
  }

shrirambalakrishnan

 const resolvers = {
    UserType: {
      posts: (parent, _, ctx) => {
        return ctx.postsLoader.load(parent.id);
      }
    },
    Query: {
      users: async () => {
        try {
          return await User.findAll()

shrirambalakrishnan

const resolvers = {
  UserType: {
    posts: (parent) => {
      return postsLoader.load(parent.id);
    }
  },
  Query: {
    users: async () => {
      try {
        return await User.findAll()

shrirambalakrishnan

const DataLoader = require('dataloader');

const postsLoader = new DataLoader( async (userIds) => {
  // Assume, userIds = [ 1, 2 ]
  
  let posts = await Post.findAll( { where: { userId: userIds } } );
  // posts = [ {title: "A", userId: 1}, {title: "B", userId: 1}, {title: "C", userId: 2} ]
  
  let postsGroupedByUser = userIds.map ( userId => {
    return posts.filter( post => post.userId == userId );

shrirambalakrishnan

const resolvers = {
  UserType: {
    posts: async (parent) => {
      return await Post.findAll({where: {userId: parent.id}});
    }
  },
  Query: {
    users: async () => {
      try {
        return await User.findAll()

shrirambalakrishnan

const resolvers = {

  Query: {
    users: async () => {
      try {
        let users = await User.findAll()
        let userIds = users.map( user => user.id)
        let posts = await Post.findAll({where: {userId: userIds}});

        let usersData = users.map( user => {

shrirambalakrishnan

const typeDefs = gql`
  type PostType {
    title: String
    description: String
  }

  type UserType {
    id: Int
    name: String
    email: String