ViewModelBase observable properties wrapper class

viewmodelbase.js

(function(ko){
  
  ko.ViewModel = function ViewModel(){
    Object.getOwnPropertyNames(this)
    .map(name => ({
      name, 
      desc: Object.getOwnPropertyDescriptor(this, name)
    }))
    .filter(o => o.desc.configurable)
    .forEach(o => {
      let obs = ko.observable(this[o.name]);
      Object.defineProperty(this, o.name, {
        enumerable: true,
        configurable: true,
        get: obs,
        set: obs
      });
    });


    let proto = Object.getPrototypeOf(this);
    Object.getOwnPropertyNames(proto)
    .map(name => ({
      name, 
      desc: Object.getOwnPropertyDescriptor(proto, name)
    }))
    .filter(o => o.desc.configurable)
    .filter(o => 'get' in o.desc)
    .forEach(o => {
      let comp = ko.pureComputed({
        read: o.desc.get.bind(this),
        write: o.desc.set ? o.desc.set.bind(this) : null
      });
      Object.defineProperty(this, o.name, {
        enumerable: true,
        configurable: true,
        get: comp,
        set: o.desc.set ? comp : undefined
      });
    });
  }


  ko.ViewModel.prototype.with = function(obs){
    return ko.pureComputed(() => obs());
  };
  
})(ko);

/*
  usage with ES6
  
  class ViewModel extends ViewModelBase {
     
     this.name = '';
     
     constructor(_name = "stranger"){
        this.name = _name;
        this.with(()=> this.name).subscribe((value)=> console.log( "Hello! " + value ) );  
        
        super(); //here the esx magic, e.g. 'this.name' became observable property transparent for syntax...   
     }
     
     get Greeting = function() {
        return this.name + ", howd'y?";
     }
     }
  }
  
*/

It will not compile, since having undefined this reference in ctor, which is forbidden, according to the latest es6 document drafts. There is possible ways to fix issue, trying to keep same expressional level, wrapping properties transparently within inherited class ctor.

• move functionality out of ctor into own function method
• decouple approach independently, using es6 generics
• use property accessor instance as parameter to base class .ctor, having default to be set as es6 default parameter expression
• extend 'with' fiction prototype, to implement or reference actual wrapper functionality
  (which seems as the most naive but powerful approach, when done using es6 arrow functions, which is easy to implement )

http://www.es6fiddle.com/iekq7bdq/

http://www.es6fiddle.com/iekqixi2/