node.js - inserting document of collections to another collections in mongodb -

i have 2 different collection of documents in mongodb database. in recruits collection have plenty of documents. , want add document recruit collections employee collections here part of code

function register(){         $http({             url:'/employee',             method:'post',             data:data // data findbyid query.         }).then(function(result){             vm.cancel();             vm.toast();         },function(err){             console.log(err);         }) 

here data findbyid recruits collections. same data want store in employees collection.i tried so:

var emp = require('../models/employees.js');  router.post('/',function(req,res){ console.log(req.body); var register = new emp(req.body); //console.log(register); register.save(function(err, respond) {     if (err) {         throw err;     } else {         res.json(respond);     } }) }); 

i think fine code console shows me

mongoerror: e11000 duplicate key error index: humanresource.employees.$_id_ dup  key: { : objectid('57395146b4c73790056a3770') } 

any 1 suggest me how insert such document in collections.

you error saying document creating has _id exists in employees collection. problem receiving recruit data , directly passing employees collection along _id passed recruit. should try copying data excluding _id field. mongo automatically generate _id employees collection. this,

var emp = require('../models/employees.js'); router.post('/',function(req,res){       console.log(req.body);        delete req.body._id;       var register = new emp(req.body);       register.save(function(err, respond) { if (err) {       throw err; } else {      res.json(respond); } });