index.js

import { ApolloServer, gql, UserInputError } from "apollo-server";
import { v1 as uuid } from "uuid";

const persons = [
  {
    name: "Alejandro",
    phone: "3364012345",
    street: "J. J. Pastor",
    city: "La Emilia",
    id: "00000000001",
  },
  {
    name: "Facundo",
    phone: "3364112211",
    street: "Av. Siempre Viva",
    city: "La Emilia",
    id: "00000000002",
  },
  {
    name: "Melisa",
    street: "24 de abril",
    city: "La Emilia",
    id: "00000000003",
  },
];

const typeDefs = gql`
  enum YesNo {
    YES
    NO
  }

  type Address {
    street: String!
    city: String!
  }

  type Person {
    name: String!
    phone: String
    address: Address!
    id: ID!
  }

  type Query {
    personCount: Int!
    allPersons(phone: YesNo): [Person]!
    findPerson(name: String!): Person
  }

  type Mutation {
    addPerson(
      name: String!
      phone: String
      street: String!
      city: String!
    ): Person
    editPhone(name: String!, phone: String!): Person
  }
`;

const resolvers = {
  Query: {
    personCount: () => persons.length,
    allPersons: (root, args) => {
      if (!args.phone) return persons;

      return persons.filter((person) => {
        return args.phone === "YES" ? person.phone : !person.phone;
      });
    },
    findPerson: (root, args) => {
      const { name } = args;
      return persons.find((person) => person.name === name);
    },
  },
  Mutation: {
    addPerson: (root, args) => {
      if (persons.find((p) => p.name === args.name)) {
        throw new UserInputError("Name must be unique");
      }
      const person = { ...args, id: uuid() };
      persons.push(person); //update database
      return person;
    },
    editPhone: (root, args) => {
      const personIndex = persons.findIndex((p) => p.name === args.name);
      if (personIndex === -1) return null;

      const person = persons[personIndex];

      const updatedPerson = { ...person, phone: args.phone };
      persons[personIndex] = updatedPerson;

      return updatedPerson;
    },
  },
  Person: {
    address: (root) => {
      return {
        street: root.street,
        city: root.city,
      };
    },
  },
};

const server = new ApolloServer({ typeDefs, resolvers });

server.listen().then(({ url }) => console.log(`Server ready at ${url}`));