app.js

const express = require("express");
const bodyParser = require("body-parser");
const mongoose = require("mongoose");
const _ = require("lodash");
const app = express();
require('dotenv').config();

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

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

mongoose.connect("mongodb+srv://admin-shiv:Test123@cluster0.rbffr.mongodb.net/todolistDB");

// Creating Schema
const itemsSchema = {
  name: String
};

// Creating the model
const Item = mongoose.model("Item", itemsSchema);

// Creating new documents
const item1 = new Item({
  name: "Welcome to your todolist!"
});

const item2 = new Item({
  name: "Hit the + to add new item to your list."
});

const item3 = new Item({
  name: "<-- Hit this to delete the item."
});

const defaultItems = [item1, item2, item3];
const listSchema = {
  name: String,
  items: [itemsSchema]
};

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


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

  Item.find({}, function (err, founditems) {

    if (founditems.length === 0) {
      Item.insertMany(defaultItems, function (err) {
        if (err) {
          console.log(err);
        } else {
          console.log("Succesfully saved default items to DB.");
        }
      });
      res.redirect("/");
    } else {
      res.render("list", { listTitle: "Today", newListItems: founditems });
    }
  });
});

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

  List.findOne({ name: customListName }, function (err, foundList) {
    if (!err) {
      if (!foundList) {
        const list = new List({
          name: customListName,
          items: defaultItems
        });
        list.save();
        res.redirect("/" + customListName);
      } else {
        res.render("list", { listTitle: foundList.name, newListItems: foundList.items });
      }
    }
  });


});



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

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

  const item = new Item({
    name: itemName,
  })

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

});

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

  if (listName === "Today") {
    Item.findByIdAndRemove(checkedItemId, function (err) {
      if (!err) {
        console.log("Successfully deleted the items.")
      }
    });
    res.redirect("/");
  } else {
    List.findOneAndUpdate({ name: listName }, { $pull: { items: { _id: checkedItemId } } }, function (err, foundList) {
      if (!err) {
        res.redirect("/" + listName);
      }
    })
  }

})


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

let port = process.env.PORT;
if (port == null || port == "") {
  port = 3000;
}

app.listen(port, function () {
  console.log("Server has started successfully");
});