ExpressJS: API Template for getter from Database

expressjs.api.config.js

/**
 * Route Template: Config
 * Path: ./expressjs.api.config.js
*/
var config = {
  "pathRoute": "/main",
  "dbConfig": { 
    "path": "mongodb://localhost:27017/test",
    "conf": {
      "useNewUrlParser": true,
      "useUnifiedTopology": true,
      "useCreateIndex": true,
      "useFindAndModify": false
  }
  },
  "someOtherConfig": ""
};

module.exports = config;

expressjs.api.models.js

/**
 * Mongoose MongoDB Model: Mongoose Users Model
 * Path: ./expressjs.api.models.js
*/
var mongoose = require("mongoose");
var config = require("../expressjs.api.config");

var dbconn = null;
function getDBInstance() {
    try {
        if (dbconn != null) { return dbconn; }
        else {
            dbconn = mongoose.connect(config.dbConfig.path, config.dbConfig.conf).catch(error => { console.log(error) });
            return dbconn; 
        }
    } catch (e) {
        return e;
    }
}
getDBInstance();
mongoose.connection.on('error', err => { console.log(err); });

const UsersSchema = new mongoose.Schema(
  { type: { type: String, enum: ['employee', 'intern'], required: true }, username: { type: String, required: true } },
  { collection: 'users' }
)
UsersSchema.index({ slug: 1, userid: 1 }, { unique: true });
const usermodel = dbconn.model('Users', UsersSchema);
await usermodel.createCollection();

module.exports = {
  "users": usermodel,
  "conn": getDBInstance()
}

expressjs.routes.get.template.js

/**
 * Route Template: API Get Request
 * Path: ./templates/expressjs.routes.get.template.js
*/

function getRequest(req, res, next) {
  const Schema = require("./expressjs.api.models.js")["users"];
  var response = await Schema.find();
  res.send(response);
}