debug-with-proxies.js

return new Proxy(this, {
 get: function(target, prop) {
   var funcOrProp = target[prop];

   if (typeof funcOrProp === 'function') {
     return function() {
       var result = funcOrProp.apply(target, arguments);
       console.log(prop + '(' + [].join.call(arguments, ',') + ') -> ' + JSON.stringify(result));
       return result;
     }
   } else {
     console.log('GET', prop, '->', funcOrProp);
     return funcOrProp;
   }
 },
 set: function(target, prop, value) {
   console.log('SET', prop, 'to', value);
   target[prop] = value;
 }
});