02-get-example.js

const user = {
  firstName: "John",
};

const getHandler = (obj, prop) => {
   // get object attributes
   if(prop in obj) {
     return obj[prop];
   }
   
  // Extension - Custom attribute
   if(prop === "nickname") {
     return "Johnny";
   }
   
  // Handle error
   return undefined;
}

const userProxy = new Proxy(user, {
  get: getHandler,
});


console.log(userProxy.firstName); // "John"

console.log(userProxy.nickname); // "Johnny"

console.log(userProxy.age); // undefined