Question

这是我从console.log(objects)得到的东西：

{
    "_id" : "5bb20d7556db6915846da55f",
    "gallary" : {
        "profilepic" : [
            "1",
            "2"
        ]

    }
},
{
    "_id" : "5bb20d7556db6915846da55f",
    "gallary" : {
        "profilepic" : [
            "3",
            "4"
        ]

    }
}

我有一个输入数组，例如：let uniqueIDs = ["0","1","10"]。我必须检查gallary.profilepic是否给定输入值可用？假设不可用，则意味着我必须推入一个数组并返回结果。

我的代码：

let uniqueIDs = ["0","1","10"]
db.Gallary.find()
.forEach(function(objects){
    console.log(objects);
    // Here your JS code has to come
})

预期输出：

["0", "10"]

Answer 1

过滤UPIDs数组，检查其中的哪些项目未包含在regularStudent数据的members属性中：

let UPIDs = ["0","1","10"];
const data = [{
    "_id" : "5bb20d7556db6915846da55f",
    "members" : {
        "regularStudent" : [
            "1",
            "2"
        ]

    }
},
{
    "_id" : "5bb20d7556db6915846da55f",
    "members" : {
        "regularStudent" : [
            "3",
            "4"
        ]

    }
}];

const regularStudents = data.map(d => d.members.regularStudent).flat();
console.log(UPIDs.filter(a => !regularStudents.includes(a)));

Answer 2

您可以将所有ID组成一个数组（在我的示例中，我使用了reduce），然后filter列出了该数组中未出现的UPID中的所有那些元素。

const data = [{"_id":"5bb20d7556db6915846da55f","members":{"regularStudent":["1","2"]}},{"_id":"5bb20d7556db6915846da55f","members":{"regularStudent":["3","4"]}}];
const UPIDs = ["0","1","10"];

// Concatenate the ids in the data together
const ids = data.reduce((acc, c) => acc.concat(c.members.regularStudent), []);

// `filter` out the elements in UPIDs that aren't in the ids array
const out = UPIDs.filter(el => !ids.includes(el));

console.log(out);

为澄清起见进行更新：

这是您的代码与我的代码的结合：

let UPIDs = ['0', '1', '10'];

db.Groups.find().forEach(function(objects){
  const ids = objects.reduce((acc, c) => acc.concat(c.members.regularStudent), []);
  const out = UPIDs.filter(el => !ids.includes(el));  
  console.log(out);
});

Answer 3

我首先要获取数据库中与您要输入的数据匹配的所有值（否则它将加载您的所有集合条目），然后查看缺少的字符串。最后，如有必要，推送一个新条目。

const UPIDs = ['0','1','10'];

const entries = await db.Groups.find({
  'members.regularStudent': {
     $in: UPIDs,
  },
});

// Get the strings that are not in the DB
const missing = UPIDs.filter(x => !entries.some(y => y.members.regularStudent.includes(x)));

// Push the missing str in DB
if (missing.length) {
  const obj = new model({
     members: {
        regularStudent: missing,
     },  
  });

  // ...
}

const UPIDs = ['0', '1', '10'];

// Thx to @Andy
const entries = [{"_id":"5bb20d7556db6915846da55f","members":{"regularStudent":['1', '2']}}];

/*
const entries = await db.Groups.find({
  'members.regularStudent': {
     $in: UPIDs,
  },
});
*/

// Get the strings that are not in the DB
const missing = UPIDs.filter(x => !entries.some(y => y.members.regularStudent.includes(x)));

// Push the missing str in DB
if (missing.length) {
  console.log('Add new data for values', missing);
}

如何检查给定的输入值是否可用？在对象中

3 个答案: