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db.command.aggregate.isoDayOfWeek

1. Operator Description​

Function: Returns the ISO 8601 day of the week for a date field, which is an integer ranging from 1 (Monday) to 7 (Sunday).

Declaration: db.command.aggregate.isoDayOfWeek(<date field>)

2. Operator Parameters​

FieldTypeRequiredDescription
-ExpressionRequiredaggregate expression

3. Sample Code​

Suppose the collection dates contains the following documents:

{
  "_id": 1,
  "date": ISODate("2019-05-14T09:38:51.686Z")
}

We use isoDayOfWeek() to project the date field and obtain the corresponding ISO 8601 day of the week:

// 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,
      isoDayOfWeek: $.isoDayOfWeek('$date')
    })
    .end()
  console.log(res.data)
}

The output is as follows:

{
  "isoDayOfWeek": 2
}