描述符对象返回 undefined

Question

我想引用 descX 和 descY 但它返回 undefined..

var polar = {
  x: undefined,
  y: undefined,
  
  descX: Object.getOwnPropertyDescriptor(this, "x", {
    value: 3,
    writable: true,
    configurable: true,
    enumerable: true,
    set setX(val) {
      polar.x = val;
    }
  }),
    
  descY: Object.getOwnPropertyDescriptor(this, "y", {
      value: 4,
      writable: true,
      configurable: true,
      enumerable: true,
      set setY(val) {
        polar.y = val;
      }
  }),
}