db.command.aggregate.reverseArray

1. Operator Description

Function: Returns the given array in reverse order.

Declaration: db.command.aggregate.reverseArray(array)

2. Operator Parameters

Field	Type	Required	Description
-	Expression	Required	The parameter can be any expression that resolves to an array.

3. Sample Code

Suppose the collection stats contains the following records:

{
  "_id": 1,
  "sales": [1, 2, 3, 4, 5]
}

Retrieve sales in reverse order:

// 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('stats')
    .aggregate()
    .project({
      reversed: $.reverseArray('$sales')
    })
    .end()
  console.log(res.data)
}

The returned result is as follows:

{ "_id": 1, "reversed": [5, 4, 3, 2, 1] }