db.command.aggregate.allElementsTrue

1. Operator Description

Description: Takes an array or an expression that resolves to an array. Returns true if all elements in the array are truthy; otherwise, returns false. An empty array always returns true.

Declaration: db.command.aggregate.allElementsTrue([expression])

2. Operator Parameters

Field	Type	Required	Description
-	<Array>Expression	Required	A string expression is in the form of $ + specified field.

3. Sample Code

Suppose the collection test contains the following records:

{ "_id": 1, "array": [ true ] }
{ "_id": 2, "array": [ ] }
{ "_id": 3, "array": [ false ] }
{ "_id": 4, "array": [ true, false ] }
{ "_id": 5, "array": [ 0 ] }
{ "_id": 6, "array": [ "stark" ] }

The following code uses allElementsTrue() to determine whether all elements in the array field are truthy:

// 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('price')
    .aggregate()
    .project({
      isAllTrue: $.allElementsTrue(['$array'])
    })
    .end()
  console.log(res.data)
}

The returned result is as follows:

{ "_id": 1, "isAllTrue": true }
{ "_id": 2, "isAllTrue": true }
{ "_id": 3, "isAllTrue": false }
{ "_id": 4, "isAllTrue": false }
{ "_id": 5, "isAllTrue": false }
{ "_id": 6, "isAllTrue": true }