Unable to connect to Mongodb using moongoos

I am trying to create DB using following snippet

const express = require("express");
const bodyParser = require("body-parser");
const mongoose = require("mongoose");
const ejs = require("ejs");

const app = express();
const port = 80;

app.set('view engine', 'ejs');

app.use(bodyParser.urlencoded({extended: true}));
app.use(express.static("public"));

mongoose.connect("mongodb://localhost:27017/griData", {useNewUrlParser: true, useUnifiedTopology: true}, (err)=> {
    if(err){
        console.log(err);
    }
});
console.log(mongoose.connection.readyState);

app.get("/", (req, res)=> {
    res.render("main");
});

app.listen(port, () => {
    console.log(`Example app listening at http://localhost:${port}`);
});

but when I check dbs from mongo shell, I don't see any db. What am I missing? Thanks