CODEWITHSUNDEEP
mongodbdatemongoose
Syffys
Syffys

Reputation: 610

Increment months to a date using an element attribute

Let’s say I have a collection of subscriptions as below:

{
    "id": "8SDQ8"
    "durationInMonths": 12,
    "startDate": {
        "$date": "2020-07-03T09:14:46.609Z",
    },
    "endDate": {
        "$date": "2021-07-03T09:14:46.609Z",
    }
}

How can I add $durationInMonths to a variable date without being forced to fetch $durationInMonths beforehand (which adds an inefficient network round trip)? Something like this:

const myDate = new Date();
const sub = await Subscription.findOneAndUpdate({
    id: '8SDQ8'
}, {
    $set: {
        startDate: myDate,
        endDate: {
            $addMonths(myDate, "$durationInMonths")
        }
    }
});

Upvotes: 1

Views: 183

Answers (1)

Lauren Schaefer
Lauren Schaefer

Reputation: 706

Updated to calculate the end date in months:

db.Subscription.update(    
    {_id: "8SDQ8"
},
[
   { $set: { 
      startDate: myDate, 
      endDate: {$dateFromParts: { 
         'year' : { $year: myDate }, 
         'month' : {$add: [
                     { $month: myDate
                     },
                     "$duration"
                  ]
               }, 
         'day': { $dayOfMonth: myDate
               }
            }
         } 
      }
   }
]
)

This answer assumes you only care about the year, month, and day, but you could easily include more precise date/time info in your endDate if you wanted to.

Upvotes: 1

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