CODEWITHSUNDEEP
javascripthierarchy
dieKoderin
dieKoderin

Reputation: 1582

Access child Object in js

function Luminary(radius, orbitRadius, speed, children) {
    this.radius = radius;
    this.orbitRadius = orbitRadius;
    this.speed = speed;
    this.children = children;
}

function initSolarSystem() {
    var moon = new Luminary(0.02, 0.2, 0.0015, []);
    var earth = new Luminary(0.1, 0.7, 0.001, [moon]);
    var sun = new Luminary(0.3, 0.0, 0.0, [earth]);
    return sun;
}

var solarSystem = initSolarSystem();

  1. I have the code above in JS. How can I access for example the radius of earth using the solarSystem object? The following returns Undefined alert(solarSystem.children.radius);

  2. How should I call children in a recursive function as follows:

    function draw(obj) {
    // draw Current Object 
    if (obj.children != undefined) {
      draw(obj.children);
    }
}

draw(solarSystem);

Can Someone please help me?

Upvotes: 1

Views: 14276

Answers (2)

TessavWalstijn
TessavWalstijn

Reputation: 1736

First of all your .children is an array. so call .children[i].radius.
Second: 

if (obj.children != undefined) {
  draw(obj.children);
}

You call here once the draw function for the full children array. So you need to implement a for loop.

For this there are a lot options this is my approach:

function Luminary(name, radius, orbitRadius, speed, children = []) {
    this.name = name;
    this.radius = radius;
    this.orbitRadius = orbitRadius;
    this.speed = speed;
    this.children = children;
}

function initSolarSystem() {
    var moon = new Luminary("moon", 0.02, 0.2, 0.0015);
    var earth = new Luminary("earth", 0.1, 0.7, 0.001, [moon]);
    var sun = new Luminary("sun", 0.3, 0.0, 0.0, [earth]);
    return sun;
}

var solarSystem = initSolarSystem();

function draw(obj) {
    // Draw current object.
    for (let key in obj.children)
      if (obj.children.hasOwnProperty(key)) {
        //if (typeof(obj.children) == "array") {
      	  console.log(obj.children[key].radius);
          draw(obj.children[key]);
        }
}

draw(solarSystem);

Upvotes: 2

gurvinder372
gurvinder372

Reputation: 68393

I have the code above in JS. How can I access for example the radius of earth using the solarSystem object? The following returns Undefined alert(solarSystem.children.radius);

solarSystem.children is an array, so use solarSystem.children[0].radius

How should I call children in a recursive function as follows.

function draw(obj) 
{
  // draw Current Object

  if (obj.children != undefined) 
  {
    obj.children.forEach( s => draw(s) ); //invoke draw in a loop
    //draw(obj.children[0]); //use 
  }
}

draw(solarSystem);

Upvotes: 3

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