Can I extend Proxy with an ES2015 class?

Well, I had forgotten about this question, but someone recently upvoted it. Even though you technically can’t extend a proxy, there is a way to force a class to instantiate as a proxy and force all its subclasses to instantiate as proxies with the same property descriptor functions (I’ve only tested this in Chrome):

class ExtendableProxy {
    constructor() {
        return new Proxy(this, {
            set: (object, key, value, proxy) => {
                object[key] = value;
                console.log('PROXY SET');
                return true;
            }
        });
    }
}

class ChildProxyClass extends ExtendableProxy {}

let myProxy = new ChildProxyClass();

// Should set myProxy.a to 3 and print 'PROXY SET' to the console:
myProxy.a = 3;