Bindable Demo

index.js

function Bindable(ClassRef, onChangeMethodName){
  class BindableClass{
    constructor(...args){
      const instance = new (ClassRef.bind(this))(...args);
      
      for(const k in instance){
        if(instance.hasOwnProperty(k)){
          const initialValue = instance[k];
          const privatePropertyName = `_${k}`;
          instance[privatePropertyName] = initialValue;
          Object.defineProperty(instance, k, {
            get: function(){
              return instance[privatePropertyName];
            },
            set: function(value){
              if(instance[privatePropertyName] !== value){
                const oldValue = instance[privatePropertyName];
                instance[privatePropertyName] = value;
                
                if(
                  typeof onChangeMethodName === 'string' &&
                  ClassRef.prototype.hasOwnProperty(onChangeMethodName) &&
                  instance[onChangeMethodName] instanceof Function
                ){
                  const onChange = instance[onChangeMethodName];
                  
                  onChange(k, value, oldValue);
                }
              }
            }
          });
        }
      }
      
      return instance;
    }
  }
  return BindableClass;
}

class Comp {
  constructor(){}
  
  m = 'p';
  h = undefined;
  
  help(...args){
    console.log(JSON.stringify(args, null, '\t'));
  }
}

const BC = Bindable(Comp, 'help');
const bc = new BC();
bc.m = 'T';
bc.h = 'L';

console.log('\n\n\n');

Automatically track the changes of all pre-initialized properties of a class.

ES6+, Stage 0

Try it here: http://babeljs.io/repl/