Proxy

Proxy可以取消代理

var obj = {
        a: 1
    },
    handles = {
        get(target, key, context) {
            console.log('accessing:', key);
            return target[key];
        }
    },
    { proxy: pobj, revoke: prevoke } = Proxy.revocable(obj, handles);

console.log(pobj.a);
// accessing: a
// 1

prevoke();

pobj.a;
// Uncaught TypeError: Cannot perform 'get' on a proxy that has been revoked