Mongoose发现两个日期之间的差异

Question

im试图计算vacations集合中每个文档的endDate和startDate之间的差异，以找到employee有多少假期？：

const employee = await Employee.findOne({ nameAR: req.body.name });
const vacations = await Vacation.find({ employeeId: employee._id });
let numberOfDays = 0;
vacations.map((vacation) => {
Vacation.aggregate([
{
$project: {
_id: vacation._id,
start: vacation.startDate,
end: vacation.endDate,
result: {
$subtract: ["$end", "$start"],
},
},
},
]).exec(function (err, diff) {
vacationCount.numberOfDays = vacationCount.numberOfDays + diff;
});
});

map为employee和aggregate循环vacations数组，以查找每个vacation文档的日期之间的差异，将其存储在变量numberOfDay中，并添加下一个。

我有两个问题：第一个：exec方法返回一个对象数组，我不想要它，我只希望它返回result，因为我不想再次映射

第二个也是大的：result返回null，这意味着aggregate甚至不能正常工作

我已经确保employee和vacations数据成功地提取

注意：startDate和endDate在某些文档中可能是null。

假期返回的文档将是这样的：

[
{
"_id": "631b59a8f25e201029953b31",
"employeeId": "631b595578dae2d46f112389",
"type": "Annual",
"startDate": "2022-09-09T00:00:00.000Z",
"endDate": "2022-09-14T00:00:00.000Z",
"numberOfHours": null,
"status": "approved",
"__v": 0
},
{
"_id": "631b59d9f25e201029953b3d",
"employeeId": "631b595578dae2d46f112389",
"type": "Day time leave",
"startDate": null,
"endDate": null,
"numberOfHours": "4",
"status": "approved",
"__v": 0
},
{
"_id": "631b59dbf25e201029953b40",
"employeeId": "631b595578dae2d46f112389",
"type": "Day time leave",
"startDate": null,
"endDate": null,
"numberOfHours": "5",
"status": "approved",
"__v": 0
},
]

提前感谢

Answer 1

试试这个，告诉我它是否适合你：

// Finding particular Employee details from employee collection
const employee = await Employee.findOne({ nameAR: req.body.name });
// Stores Total Number of Vacation Days 
let numberOfDay  = 0;
/* Finding all matching vacation records from vaction collection,aggregate them 
and calculate no. of days between end and start date, stores it to numberOfVacationDays.*/
const vacations = await Vacation.aggregate([
{
$project: {
_id: "$_id",
start: "$startDate",
end: "$endDate",
numberOfVacationDays: {
$divide: [
{
$subtract: [
{
"$toDate": "$endDate"
},
{
"$toDate": "$startDate"
}
]
},
//returned mills can be converted to day by dividing by 86400000 (number of milliseconds in 24 hours)
86400000 
]
},
},
},
{
"$match": {
employeeId: employee._id 
}
}
]).exec();
// Once we have all vacation days of employee ,
//we can calculate total Number Of Vacation Days and store it in numberOfDay
vacations.forEach((vacation) =>{
if(vacation.numberOfVacationDays){
numberOfDay  += vacation.numberOfVacationDays;
}
});