ES6 Rest Parameter

by Rich Costello

JavaScript

function pick(object, ...keys) {
  let result = Object.create(null);
  // start at the second parameter
  for (let i = 0, len = keys.length; i < len; i++) {
    result[keys[i]] = object[keys[i]];
  }
  return result;
}
let book = {
  title: "Understanding ECMAScript 6",
  author: "Nicholas C. Zakas",
  year: 2016
};
let bookData = pick(book, "author", "year");

console.log(bookData.author);
console.log(bookData.year);