db.command.aggregate.month
1. Operator Description
Function: Returns the month for a date field, which is an integer between 1 and 12.
Declaration: db.command.aggregate.month(<date field>)
2. Operator Parameters
Field | Type | Required | Description |
---|---|---|---|
- | Expression | Required | aggregate expression |
3. Sample Code
Suppose the collection dates
contains the following documents:
{
"_id": 1,
"date": ISODate("2019-05-14T09:38:51.686Z")
}
We use month()
to project the date
field and obtain the corresponding month:
// Sample code in the Cloud Function environment
const tcb = require('@cloudbase/node-sdk')
const app = tcb.init({
env: 'xxx'
})
const db = app.database()
const $ = db.command.aggregate
const _ = db.command
exports.main = async (event, context) => {
const res = await db
.collection('dates')
.aggregate()
.project({
_id: 0,
month: $.month('$date')
})
.end()
console.log(res.data)
}
The output is as follows:
{
"month": 5
}