db.command.aggregate.arrayToObject

1. Operator Description

Function: Converts an array to an object.

Declaration:

Two forms

1. Pass in a two-dimensional array where each sub-array must have a length of 2, with the first element as the field name and the second as the field value.

db.command.aggregate.arrayToObject([ [key1, value1], [key2, value2], ... ])

2. Pass in an array of objects where each object must contain the fields k and v, specifying the field name and field value respectively.

db.command.aggregate.arrayToObject([ { "k": key1, "v": value1 }, { "k": key2, "v": value2 }, ... ])

2. Operator Parameters

Field	Type	Required	Description
-	<Array> Array Or Object	Required	as described in the declaration

3. Sample Code

Suppose the collection shops contains the following records:

{ "_id": 1, "sales": [ ["max", 100], ["min", 50] ] }
{ "_id": 2, "sales": [ ["max", 70], ["min", 60] ] }
{ "_id": 3, "sales": [ { "k": "max", "v": 50 }, { "k": "min", "v": 30 } ] }

Calculate the score of the first exam and the score of the last exam for each:

// 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

exports.main = async (event, context) => {
  const res = await db
    .collection('shops')
    .aggregate()
    .project({
      sales: $.arrayToObject('$sales')
    })
    .end()
  console.log(res.data)
}

The returned result is as follows:

{ "_id": 1, "sales": { "max": 100, "min": 50 } }
{ "_id": 2, "sales": { "max": 70, "min": 60 } }
{ "_id": 3, "sales": { "max": 50, "min": 30 } }