Express Route Parameters creating duplicate custom paths - node.js

Question

I am creating a to-do list app and I am trying to including custom routes using 'Express Route Parameters'. The program worked fine up until this point, but as soon as I tried to introduce these custom paths and log it to the console, or even add it to the database, the very first path gets added twice or logged twice. The paths added later are not duplicated, though.
app.get("/:customListName", function(req,res)
{
console.log(req.params.customListName);
/*const list = new List
({
name: customListName,
items: defaultItems
});
list.save();*/
});
For example, if the custom path added is called "home", i.e., "localhost:3000/home" and I am trying to console.log the name of the path, it will print "home" twice. Later, if I add paths like "work", "new" etc they are added (and printed) only once. Sometimes this error is also coming up:
BulkWriteError: E11000 duplicate key error collection: wolDB.items index: _id_ dup key: { _id: ObjectId('5ef4ad2110f45d54f143fa19') }
I have tried dropping the database and start afresh, drop indexes, even tried with a new database; but it seems the problem is not in the database because even without pushing it to the database, the problem persists. I tried coding the whole thing afresh, but the problem persists.
I have tried findOne() of mongoose also, but when I try to print whether the given route exists or not, for the first one it just prints "exists" twice.
List.findOne({name: customListName}, function(err, foundList)
{
if(!err)
{
if(!foundList)
console.log("Doesn't exist");
else
console.log("Exists");
}
});
Here's the GitHub link:
https://github.com/sebanti10/todolist.git

Answer 1

if you don't need the list and want to directly save to the database try using
List.create({
name: customListName,
items: defaultItems
})

Answer 2

Look at your schemas. Nowhere are you using new mongoose.Schema(). When you use mongoose.model("Item", itemsSchema) you need to pass in an actual schema, not just any object.
You need to change your so called schemes to something along the lines of:
const itemsSchema = new Schema({
name: String
});
Schema is available under mongoose, so you can either use mongoose.Schema directly or grab it const Schema = mongoose.Schema; or const { Schema } = mongoose;