JavaScript原型组织

Question

With this organisation, is it possible to reference the "id" property?

  function house(id) {  this.id = id }

  house.prototype.buy  = function() {  }
  house.prototype.sell = function() {  }

  house.prototype.buy.makeOffer=function(){
    //how can id be printed?
    console.log( 'id = ' + this.????  )      
  }

  var h = new house(1)
  h.buy.makeOffer();

I am trying to figure out the best way to organize a lot of prototypes for an object. As .buy will have a lot of sub-function an so will .sell() ie:

  h.buy.makeOffer();
  h.buy.inspect();
  h.buy.counterOffer();
  h.buy.signContact();

  h.sell.prepare()
  h.sell.advertise()
  h.sell.reviewOffer()

Answer 1

It's really not very easy to use a structure like this in Javascript:

house.prototype.buy.makeOffer=function(){
    //how can id be printed?
    console.log( 'id = ' + this.????  )      
}

The issue is that when you call that method on an instance of house like this:

var h = new house(1);
h.buy.makeOffer();

the this value in the makeOffer() method will point to the buy object in the prototype (which is your buy method) and it will NOT point to your house object. That's just how method calls work in Javascript ( this points to the object which had the method) which renders these nested methods when there's actual instance data that you want to reference via this very impractical.

---

The usual solution is to not implement the nesting. Just integrate the names without an extra layer of objects like this:

house.prototype.buyMakeOffer=function(){
    //how can id be printed?
    console.log( 'id = ' + this.????  )      
}

var h = new house(1);
h.buyMakeOffer();