javascript - 在js中访问子对象

Question

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. 我在 JS 中有上面的代码。我如何使用 solarSystem 对象访问地球的半径？以下返回 Undefined alert(solarSystem.children.radius);

2. 我应该如何在递归函数中调用子函数，如下所示:

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

有人可以帮帮我吗？

Answer 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);

solarSystem.children 是数组，所以使用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);