Greater than Condition is not working in Nodejs & Mongodb - node.js

Question

I created an API using Nodejs and mongoose,
app.js
const express = require('express')
mongoose = require('mongoose')
var cron = require('node-cron');
const app = express()
app.use(cors());
const port = 3000
bodyParser = require('body-parser');
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
Duser = require('./models/duser.Model');
cron.schedule('* 12 * * *', () => {
console.log("corn shedule");
Duser.updateMany({"devices.validity": {$gt: 0}}, {$inc: {"devices.$[].validity": -1}}, function(err) {
if(err)
{
console.log(err);
}
});
});
I update all validity decrement by 1, if validity is greater than zero but the condition is not working, the value is decrement by 1 it goes negative value. help me solve the problem
Duser.Model.js
'use strict';
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var Schema = new Schema({
phone_number: { type: String, Required: 'Phone Number cannot be left blank.' },
email: { type: String, Required: 'email cannot be left blank.' },
user_name: { type: String, Required: 'Customer Name cannot be left blank.'},
date: { type: Date, default: Date.now },
"devices": {
"type": [
{
ime_number: { type: String, Required: 'IME Number cannot be left blank.'},
device_name: { type: String, Required: 'Device Name cannot be left blank.'},
subscription_type: { type: String, Required: 'Subscription Type cannot be left blank.'},
validity: { type: Number, Required: 'Validity cannot be left blank.'},
date: { type: Date, default: Date.now },
}
]
}
}, { versionKey: false });
module.exports = mongoose.model('DUsers', Schema);

Answer 1

Try to reference the type attribute and use $elemMatch for filtering the subarray elements
cron.schedule('* 12 * * *', () => {
console.log('corn shedule');
Duser.updateMany(
{ 'devices.type': { $elemMatch: { validity: { $gt: 0 } } } },
{ $inc: { 'devices.type.$[].validity': -1 } },
function (err) {
if (err) {
console.log(err);
}
}
);
});