function pick(object) {
let result = Object.create(null);
// start at the second parameter
for (let i = 1, len = arguments.length; i < len; i++) {
result[arguments[i]] = object[arguments[i]];
}
return result;
}
let book = {
title: "Understanding ECMAScript 6",
author: "Nicholas C. Zakas",
year: 2015
};
let bookData = pick(book, "author", "year");
console.log(bookData.author); // "Nicholas C. Zakas"
console.log(bookData.year); // 2015