Javascript 将新对象值反复添加到现有对象值中

我需要写一个代码，这样的结果出来

{ username: 'Cloud', 
  species: 'sheep', 
  tagline: 'You can count on me!', 
  noises: ['baahhh', 'arrgg', 'chewchewchew'], 
  friends: [{username: 'Moo', species: 'cow'...}, {username: 'Zeny', species: 'llama'...}]
}

但我的代码当前首先打印为添加到现有对象上的新对象，当我尝试将另一个新对象添加到现有对象上并将其记录到console.log中时，它将替换最后添加的对象并仅添加新对象值

{ username: 'Cloud',
  species: 'sheep',
  tagline: 'You can count on me!',
  noises: [ 'baahhh', 'arrgg', 'chewchewchew' ],
  friends: 
   { username: 'Moo',
     species: 'cow',
     tagline: 'asdf',
     noises: [ 'a', 'b', 'c' ],
     friends: [] } }
{ username: 'Cloud',
   species: 'sheep',
   tagline: 'You can count on me!',
   noises: [ 'baahhh', 'arrgg', 'chewchewchew' ],
   friends: 
    { username: 'Zeny',
      species: 'llama',
      tagline: 'qwerty',
      noises: [ 'z', 'x', 'c' ],
      friends: [] } }

这是到目前为止我的代码。我只把animal2=animal写下来，它会替换它，这样当添加另一个新对象值时，它会将它添加到该对象中，而不是原始对象中。我需要在这里有一个循环才能工作吗

function AnimalCreator(username, species, tagline, noises) {
  var list = { 
    username: username,
    species: species,
    tagline: tagline,
    noises: noises,
    friends: []
  };

    return list;

}

function addFriend(animal, animal2) {

    animal.friends = animal2;
    animal2 = animal;


}

var sheep = AnimalCreator('Cloud', 'sheep', 'You can count on me!', ['baahhh', 'arrgg', 'chewchewchew']);
var cow =  new AnimalCreator('Moo', 'cow', 'asdf', ['a', 'b','c']);
addFriend(sheep, cow);
console.log(sheep);
var llama = new AnimalCreator('Zeny', 'llama', 'qwerty', ['z', 'x', 'c']);
addFriend(sheep,llama);
console.log(sheep);

---

我做错了什么？

你的问题似乎在

添加朋友（动物，动物2）

你设置

animal2=animal

的地方。我想你想做的是添加朋友，这可以像

function addFriend(animal, animal2) {
    var pastFriends=animal.friends;
    pastFriends.push(animal2);
    animal.friends = pastFriends;
}