Determine if an ES6 object is a proxy

extendProxyHandler.js

function extendProxyHandler(handler){
	let originalGetTrap = handler.get;
	handler.get = function(target, propKey, receiver){
		switch (propKey){
			case "_isProxy":
				return true;
				break;
			case "_proxyTarget":
				return target;
				break;
			default:
				if (typeof handler.get === "function"){
					return originalGetTrap.call(this, target, propKey, receiver);
				}
				else{
					return Reflect.get(target, propKey);
				}
				break;
		}
	};
	
	let originalSetTrap = handler.set;
	handler.set = function(target, propKey, value, receiver){
		switch (propKey){
			case "_isProxy":
				break;
			case "_proxyTarget":
				break;
			default:
				if (typeof handler.set === "function"){
					return originalSetTrap.call(this, target, propKey, value, receiver);
				}
				else{
					return Reflect.set(target, propKey, value);
				}
				break;
		}
	};
}

let proxyHandler = {
	 get: function(target, propKey, receiver){
		//log the method calls
		if (typeof target[propKey] === "function"){
			console.log("intercepting call to method: " + propKey ); 
		}
		return Reflect.get(target, propKey);
	}
};

class Person{
	constructor(name){
		this.name = name;
	}
	
	sayHiTo(someone){
		return `Hi ${someone} I'm ${this.name}`;
	}
	
}

let p1 = new Person("Francois");

let proxiedP1 =  new Proxy(p1, proxyHandler);
console.log(proxiedP1.sayHiTo("Didier"));

console.log("-------------------");

console.log("After enhanding the proxy handler");
extendProxyHandler(proxyHandler);
let proxiedP1_2 = new Proxy(p1, proxyHandler);
console.log(proxiedP1_2.sayHiTo("Didier"));

console.log("isProxy: " + proxiedP1_2._isProxy);

let p2 = proxiedP1_2._proxyTarget;

console.log("p1===p2: " + (p1===p2));