arrays - 如何从用户已选择城市键的数组中获取结果，如果用户选择了城市，这些结果也将来自城市模型中未选择的城市

Question

城市模型

[
  {
    "_id": '1',
    "city":'A',
  },
   {
    "_id": '2',
    "city":'B',
  },
   {
    "_id": '3',
    "city":'C',
  },
  {
    "_id": '4',
    "city":'D',
  },
  {
    "_id": '5',
    "city":'E',
  }
]

用户模型

[
  {
    "_id": '1',
    "user":'sams',
    "selected_city":['1','2']
  } 
]

想要得到结果

[

{

  "_id": "1",

  "user": "sams",

"selected_city": [
      "1",
      "2"
    ],

"not_selected": [
      "3",
      "4",
      "5"
    ]
 
  }
]

Answer 1

尝试:

const cities = [
  {
    "_id": '1',
    "city":'A',
  },
   {
    "_id": '2',
    "city":'B',
  },
   {
    "_id": '3',
    "city":'C',
  },
  {
    "_id": '4',
    "city":'D',
  },
  {
    "_id": '5',
    "city":'E',
  }
];


const users = [
  {
    "_id": '1',
    "user":'sams',
    "selected_city":['1','2']
  } 
];

const result = users.map(user => {
  user.not_selected = cities
    .filter(city => !user.selected_city.includes(city._id))
    .map(city => city._id)
  return user;
});

console.log(result);