Question

The method obj2.method1, in the code below, is called from another object.
How do I bind the “this context” so that I can refer to obj1 from obj2?

var singleton = {
  obj1 : {
     a : 5
  },

  obj2 : {
    method1 : function(){
       this.obj1.a; //undefined
    }
  }
}

I tried using underscore _.bindAll() – something along these lines – but failed …

var singleton = {
  obj1 : {
     a : 5
  },

  obj2 : {
    method1 : function(){
       this.obj1.a; //undefined
    }
  },
  init : function(){
       _.bind(this, obj2.method1)
  }
}

singleton.init();

Thanks 🙂

Answer 1

1. You need to reassign singleton.obj2.method2() with the results of _.bind():

   // in .init():

   this.obj2.method1 = _.bind(this.obj2.method1, this)

2. To have singleton.init() have a proper this when called, you need to specify it explicitly:

   singleton.init.call(singleton)

Full demonstration here. But remember, the Singleton pattern is bad, m’kay?