Just like the weather widget, we will write the client side of the note application with Angular 2. When the application starts, it will try to download the list of notes. If the user is not logged in, we will get an Unauthorized error (status code 401) and show the login form. Otherwise, we can show the menu with all notes, a logout button, and a button to create a new note. When clicking on a note, that note is downloaded and the user can edit it in the note editor. If the user clicks on the new button, the user can write the new note in the (same) note editor.
The server uses a cookie to manage the session, so we do not have to do that manually on the client side.
We start with almost the same HTML file saved as static/index.html:
<!DOCTYPE HTML>
<html>
<head>
<title>My Notes</title>
<link rel="stylesheet" href="style.css" />
</head>
<body>
<div id="wrapper...