exampleObserver.js

var renderManObserver = function renderManObserver(value) {
  console.log('Re-rendering...', `<blink>${ value }</blink>`);
};

var o = {
  name: ''
};

var makeReactive = function makeReactive(obj, observer) {
  Object.keys(obj).map(function (value) {
    Object.defineProperty(obj, value, {
      get() {
        return value;
      },
      set(newVal) {
        value = newVal;
        observer(value);
      }
    });
  });
}

makeReactive(o, renderManObserver);

o.name = 'Duder Manchild';