//原型式继承
function inheritObject(o) {
  //声明一个过渡函数对象
  function F() {
    //过渡对象的原型继承父对象
      F.prototype = o;
  }
  //返回过渡对象的一个实例，该实例的原型继承了夫对象
  return new F();
}

//测试

let book = {
  name: 'js books',
  alikeBook: ['css book', 'html book']
};

let newBook = inheritObject(book);
newBook.name = 'ajax book';
// newBook.alikeBook.push('xml book');

console.log(newBook.name);           //ajax book
console.log(newBook.alikeBook);      //undefined

console.log(book.name);              //js books
console.log(book.alikeBook);         //['css book', 'html book']

想问一下，问什么newBook.alikeBook是undefined？