ES6 Class wait for request before moving on, after initializing a new class?

Question

I am trying to make a new class like this:

const request = require("request");

class Person {
    constructor(personName) {
        request(`http://personapi.com/name/${personName}`, (err, res, body) => {
            body = JSON.parse(body);
            this.name = body.name;
            this.age = body.age;
            this.gender = body.gender;
        }
    }
}

let person = new Person("Donald Trump");
console.log(person.name);

Doing the above does not work, because it creates the new person which has no attributes yet, because the request is not done loading yet. If I do something like:

let person = new Person("Donald Trump");
setTimeout(() => {
    console.log(person.name);
}, 1000);

It works fine. I know this is because it's asynchronous. How do I make sure let person is not actually set, before the request is done? Don't worry about code blocking.

Answer 1

Maybe just do a request before instantiating a Person:

const request = require("request");

class Person {
    constructor(obj) {
            this.name = obj.name;
            this.age = obj.age;
            this.gender = obj.gender;
    }
}

let person;

request(`http://personapi.com/name/${personName}`, (err, res, body) => {
    body = JSON.parse(body);
    person = new Person(body);
});

Answer 2

I'd suggest storing the promise in property:

const request = require("request");

class Person {
    constructor(personName) {
        this.ready = 
          request(`http://personapi.com/name/${personName}`, (err, res, body) => {
              body = JSON.parse(body);
              this.name = body.name;
              this.age = body.age;
              this.gender = body.gender;
          });
    }
}

let person = new Person("Donald Trump");
person.ready.then(_ => console.log(person.name));

Although seems a little hacky. Another option that looks better and also encapsulates person related logic inside Person class:

const request = require("request");

class Person {
    constructor({name, age, gender}) {
      this.name   = name;
      this.age    = age;
      this.gender = gender;
    }

    static fromName(name) {
      return request(`http://personapi.com/name/${personName}`)
        .then(resp => resp.json())
        .then(body => new this(body));
    }
}

Person
  .fromName("Donald Trump")
  .then(person => console.log(person.name);