Async JS

async.js

// fetch("http://localhost:3000/people")
//     .then(response => response.json())
//     .then(people => {
//         return people.map(person => {
//             return fetch("http://localhost:3000/person" + person.id + "/address")
//                 .then(response => response.json())
//                 .then(address => {
//                     person.address = address;
//                     return person;
//                 });
//         });
//     })
//     .then(people => {
//         Promise.all(people).then(result => {
//             console.log(result);
//         });
//     });

const URL = 'https://swapi.co/api/';

fetch(`${URL}people`)
  .then(response => response.json())
  .then(people => {
    return people.results.map(person => {
      return fetch(person.homeworld)
        .then(response => response.json())
        .then(homeworld => {
          person.homeworld = homeworld;
          return person;
        });
    });
  })
  .then(people => {
    Promise.all(people).then(result => {
      console.log(result);
    });
  });