How to do full text search in all collections in mongodb without specifying the collection name

[Rigin Oommen]

var express = require('express');
var router = express.Router();

var mongoose = require('mongoose');

var db = mongoose.connection;

router.param('params', function(req, res, next, params) {
  mongoose.connection.db.collectionNames(function (err, names) {
          var searchresults = [];
        for(var index in names) {
            var collectionLength = (names.length)-1;
            var collectionName = names[index].name;
            db.collection(collectionName).find({$text: {$search: params}}).toArray(function(err, results) {
                if(results !== null) {
                    searchresults.push(results);
                }
                if(collectionLength == index) {
                    console.log(index);
                    req.request = searchresults;
                    return next();
                } else    {
                    console.log("Loop Continues")
                }
            });
        }
    });

});

router.get('/search/:params', function (req, res, next) {
    res.json(req.request);
});


How to do the full text search and get combined results in a single response