app.js

const express = require("express");
const bodyParser = require("body-parser");
const mongoose = require('mongoose');
const date = require(__dirname + "/date.js");
const _ = require('lodash');

const app = express();


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

app.use(bodyParser.urlencoded({
  extended: true
}));

app.use(express.static("public"));

async function main() {
  mongoose.set('strictQuery', false);
  await mongoose.connect("mongodb+srv://admin_ayush:Test123@cluster0.aurzbxr.mongodb.net/todolistDB", {useNewUrlParser: true});

  const todolistSchema = new mongoose.Schema({
    name: String
  });

  const listSchema = new mongoose.Schema({
    name: String,
    items: [todolistSchema]
  });

  const Item = mongoose.model("Item", todolistSchema);
  const List = mongoose.model("List", listSchema);

  const item1 = new Item({
    name: "Welcome to the todolist"
  });

  const item2 = new Item({
    name: "Hit the + button to add new items."
  });

  const item3 = new Item({
    name: "<-- hit this to delete items."
  });

  const defaultItems = [item1, item2, item3];


  app.get("/", function(req, res) {

    const day = date.getDate();

    Item.find(function(err, items) {

      if (items.length === 0) {

        Item.insertMany(defaultItems, function(err) {
          if (err) {
            console.log("Error under insert " + err);
          }
        });
        res.redirect("/");
      } else {
        res.render("list", {
          listTitle: day,
          items: items
        });
      }
    });

  });

  app.post("/delete", function(req, res) {
    const itemId = req.body.checkbox;
    const listName = req.body.listName;

    if (listName === date.getDate()) {
      Item.deleteOne({_id: itemId}, function(err) {
        if (!err) {
          res.redirect("/");
        }
      });
    } else {
      List.findOneAndUpdate({name: listName}, {$pull:{items:{_id: itemId}}}, function(err){
        if (!err) {
          res.redirect("/"+listName);
        }
      })
    }

  });

  app.get("/:customList", function(req, res) {
    const customListName = _.capitalize(req.params.customList);

    List.findOne({ name: customListName }, function(err, foundList) {

      if (!err) {

        if (!foundList) {
          // Newly created list
          const list = new List({
            name: customListName,
            items: defaultItems
          });
          list.save();
          res.redirect("/" + customListName);
        } else {
          // showing lists
          res.render("list", {
            listTitle: customListName,
            items: foundList.items
          });
        }
      }
    });

  });

  app.post("/:customList", function(req,res){

    const customListName = req.params.customList;

    List.findOneAndUpdate({name: customListName},{items: "New Item"});
    res.redirect("/"+ customListName);
  });

  app.get("/about", function(req, res) {
    res.render("about");
  });

  app.post("/", function(req, res) {

    const newItem = req.body.newItem;
    const listName= req.body.list;

    const item = new Item({
      name: newItem
    });

    if (listName === date.getDate()) {
      item.save();
      res.redirect("/");
    } else {
      List.findOne({name: listName}, function(err,foundList){
        if(!err){
          foundList.items.push(item);
          foundList.save();
        }
      });
      res.redirect("/"+listName);
    }

  });
 const port = process.env.PORT || 3000;

  app.listen(port, function() {
    console.log("Server started on port :"+ port);
  });
};

main();