如何从构造函数中的函数返回对象属性？

Question

I'm building a small world builder in JavaScript (part of a larger simulation).

I'm trying to define an object's property in the constructor function by assigning a functions output to it.

In the code below, 'this.identifier' executes like a charm, but I want to assign more complex functions to for instance 'this.gender'.

In 'this.gender' I want to use math.random.math.floor to cycle through an array (that has two values, male and female).

When I write the actual function, 'this.gender' is dropped from the new Human object.

 {
   "identifier":42,
   "lifestate":"Alive",
   "health":"100",
   "age":"10",
   "metabolism":"12",
   "econsumption":"11111",
   "parent":"yes"
}

• gender is dropped the moment I change it to a function.

I've tried using a return statement, but it makes no difference.

class Bluehuman {
  constructor() {
    this.identifier = Math.floor((Math.random() * 100));
    this.lifestate = 'Alive';
    this.health = '100';
    this.age = '10';
    this.metabolism = ['Low','Medium','High'];
    this.econsumption = '11111';
    this.parent = ['Yes','No'];
    this.gender = ['Male','Female']; // Want to change this to a function without dropping from the new Bleuhuman object
    }
  }

var bluehuman = {};
var bluehumans = [];

for (var i = 0; i < 10; i++) {
  bluehuman[i] = new Bluehuman();
  bluehumans.push(bluehuman[i]);
}

var arrayPrint = JSON.stringify(bluehumans);
console.log(arrayPrint)

How can I assign the output of a function to 'this.gender' without having it dropped from the new bluehuman object?

Answer 1

You don't need a function, an expression is just fine to solve your problem

 class Bluehuman { constructor() { this.identifier = Math.floor((Math.random() * 100)); this.lifestate = 'Alive'; this.health = '100'; this.age = '10'; this.metabolism = ['Low','Medium','High']; this.econsumption = '11111'; this.parent = ['Yes','No']; this.gender = ['Male','Female'][Math.round(Math.random())]; } } var bluehuman = {}; var bluehumans = []; for (var i = 0; i < 10; i++) { bluehuman[i] = new Bluehuman(); bluehumans.push(bluehuman[i]); } var arrayPrint = JSON.stringify(bluehumans); console.log(arrayPrint) 

Answer 2

You can just assign a function as any other value

  this.test = function() { };

you will then be able to call it as:

  new Bluehuman().test();

and if you log it to the console directly, you'll also see it:

  console.log(new Bluehuman());

If you however call JSON.stringify on it, it will be turned into a string containing only data, functions (and a lot of other things) get removed.