Update Handler Implementation

[bishal1994]

Hello , I have been trying to implement the design document for update handler in couchdb

  {
     "_id": "_design/secure",
     "_rev": "27-d7fbdd8ea925df711d2d4329dbb032c2",
     "language": "javascript",
     "updates": {
     "update": "function(doc,req){if(!doc)return[null,'Doc doesnt exists! Please Create a new 
           document']doc.secured = doc.secured == false?true:false;return [doc,'Ok,Secured']}"
            }
   }

And I want to invoke it to modifiy my docs once it is stored in couchdb . The docs will be syncing from the pouchdb that is running in a cordova app background . This is what I have tried to implement

var argv = require('minimist')(process.argv.slice(2));

var logLocation=argv.pouchlog;
var controlFileHandler=argv.controlfh;

var express = require('express')
var app = express()
var PouchDB = require('pouchdb')
let InMemPouchDB = PouchDB.defaults({db: require("memdown"), migrate: false})

app.use('', require('express-pouchdb')(InMemPouchDB, {mode:'minimumForPouchDB',logPath:logLocation}))
app.listen(3005)
var db = new InMemPouchDB('todos',{revs_limits: 1});
var remoteCouch = 'http://127.0.0.1:5984/todos';

db.changes({live: true}).on('change', console.log);
this.db = db;
db.sync(remoteCouch,{live:true,retry:true}).on('active',function(){
Update.update('_design/secure', function(doc){

console.log("Data Secured");
console.log(doc);
})

But its not working , Please can you guys help me in the implementation . The aim is to trigger the update_handler function only when the data is stored in the Couchdb ( and indicates the data syncing between multiple pouchdb is not secure unless it is stored in the couchdb ). Please help me solve the issue.