I'm unable to add data to MongoDB database - node.js

Question

I'm trying to add data in the form of users to my MongoDB database which is in my local drive, but no data is being added according to post requests on postman. I have written an API to handle this post request on userRoute file. Below is the file.
const User = require("../models/userModel");
const express =require("express");
const router = express.Router();
//Fetching all users from the database
router.route("/").get((req,res) => {
User.find()
.then(users => res.json(users))
.catch(err => res.status(400).json(`There was an error: ${err.message}`));
});
//Adding user to the database
router.route("/add").post((req,res) =>{
const username = req.body.username;
const newUser = new User({username});
newUser.save()
.then(() => res.json("User added successfully!!"))
.catch(err => res.status(400).json(`There was an error:${err.message}`))
});
module.exports = router;
Below is also my User schema in the userModel file
const mongoose = require ("mongoose");
const Schema = mongoose.Schema
const userSchema = new Schema(
{
username: {
type: String,
required: true,
unique: true,
trim: true,
minlength: 5,
maxlength: 15
}
},
{
timestamps: true
}
)
const User = mongoose.model("User",userSchema);
module.exports = User;
My server file containing the connection to the database and routing
//require the installed packages
const express = require("express");
const cors = require("cors");
const mongoose = require ("mongoose");
const res = require("express/lib/response");
const App = express();
require("dotenv").config();
//middlewares
App.use(cors());
App.use(express.json());
//setting environment variables and explicitly declared variables
const port = process.env.PORT || 3000;
const db = process.env.MONGODB_URI || "mongodb://localhost/tizi";
//routes
const exerciseRoute = require("./routes/exerciseRoute");
const userRoute = require("./routes/userRoute");
//App to use required routes(Use App.set and not App.use)
App.set("/Users",userRoute);
App.set("/Exercises",exerciseRoute);
//setting up server
App.listen(port,() =>{
console.log(`Server is running on port : ${port}`)
});
//connecting to database
mongoose.connect(db,
{
useNewUrlParser:true,
useUnifiedTopology : true
},
(err) => {
err
? console.log(`there is a problem: ${err.message}`)
: console.log("connected to database successfully");
});
//maintaining connection to database
mongoose.connection;

Answer 1

Try to use
await User.create({username});
Instead of save()