index.js

const express = require('express');
const mongoose = require('mongoose');
const ShortUrl = require('./models/shortUrl');
const app = express();


mongoose.connect("mongodb://localhost/urlshortner", {useNewUrlParser: true , 
useUnifiedTopology: true});

app.set('view engine' , 'ejs');
app.use(express.urlencoded({extended: false}));

app.get('/',async (req,res) => {
    const shortUrls = await ShortUrl.find()
    res.render('home',{shortUrls: shortUrls});
});

app.post('/shortUrl', async (req,res) => {
    await ShortUrl.create({full:req.body.fullUrl})
    res.redirect("/");
});

app.get('/:shortUrl', async (req,res) => {
    const shortUrl = await ShortUrl.findOne({short: req.params.shortUrl})
    if(shortUrl == null){
        res.sendStatus(404)
    }
    shortUrl.clicks++;
    shortUrl.save();
    res.redirect(shortUrl.full)
})

app.listen(3000);