javascript - 将数组添加到现有的嵌套数组而不重复 mongodb

Question

这是我的用户收藏

{ _id: ObjectId("589803bf53860d4a3475afa3"),
  "username": "fadeltd",
  "gender": "Male",
  "updatedAt": ISODate("2017-02-06T05:03:59.969Z"),
  "createdAt": ISODate("2017-02-06T05:03:59.969Z"),
  "shoppingList": [{
      "title": "Personal List",
      "ingredients": ["5 Eggs"]
  }]
})

我想做的是将数据推送到我的购物 list ，使用$addToSet，这样就不会出现重复的购物 list 数据

这是我的脚本

User.update({ 
        _id: ObjectId("589803bf53860d4a3475afa3"), 
        'shoppingList.title': "Personal List"
    }, 
    {
        $addToSet: {
            "shoppingList.$.ingredients": ["5 Eggs", "3 Milks"]
        }
    })

但是当我尝试该脚本时，我得到了这个

{ _id: ObjectId("589803bf53860d4a3475afa3"),
  "username": "fadeltd",
  "gender": "Male",
  "updatedAt": ISODate("2017-02-06T05:03:59.969Z"),
  "createdAt": ISODate("2017-02-06T05:03:59.969Z"),
  "shoppingList": [{
      "title": "Personal List",
      "ingredients": ["5 Eggs", ["5 Eggs", "3 Milks"]],
  }]
})

我希望成分为 ["5 Eggs", "3 Milks"] 而不是嵌套数组 ["5 Eggs", ["5 Eggs", "3 Milks"]]

Answer 1

使用$each 修饰符，允许您向数组添加多个值

User.update(
    { 
        "_id": ObjectId("589803bf53860d4a3475afa3"), 
        "shoppingList.title": "Personal List"
    }, 
    {
        "$addToSet": {
            "shoppingList.$.ingredients": { 
                "$each": ["5 Eggs", "3 Milks"] 
            }
        }
    }
)