对象中的getFullYear（）[重复]

Question

谁能解释为什么这不起作用：

var todayDate = new Date();
var todayYear = todayDate.getFullYear();

var User = {
  firstName: "John",
  lastName: "Doe",
  email: "email@email.com",
  dob: new Date(85, 1, 1),
  userBirthYear: dob.getFullYear(),
  age: todayYear - userBirthYear,
  url: "http://www.google.com",
  bio: "I love pizza",
  interests: ["food", "NBA", "movies"]
}

userBirthYear 似乎没有初始化。如果我将 userBirthYear 作为单独的变量移到对象之外，它可以正常工作。

Answer 1

dob 不是变量，它是 User 对象的属性。

但在整个对象编译完成之前，您不能直接访问对象属性

你可以这样做；

var User = {
  firstName: "John",
  lastName: "Doe",
  email: "email@email.com",
  dob: new Date(85, 1, 1), 
  age: todayYear - userBirthYear,
  url: "http://www.google.com",
  bio: "I love pizza",
  interests: ["food", "NBA", "movies"]
}
// User object now exists, modify it any way you need
 User.userBirthYear = User.dob.getFullYear();