Storing notes in the filesystem

The filesystem is an often overlooked database engine. While filesystems don't have the sort of query features supported by database engines, they are a reliable place to store files. The notes schema is simple enough that the filesystem can easily serve as its data storage layer.

Let's start by adding a function to Note.js:

get JSON() {
    return JSON.stringify({
        key: this.key, title: this.title, body: this.body
    });
}

This is a getter, which means note.JSON (no parenthesis) will simply give us the JSON representation. We'll use this later for writing to JSON files.

Take a peek at the static function mentioned in the following code:

static fromJSON(json) {
    var data = JSON.parse(json);
    var note = new Note(data.key, data.title, data.body);
    return note;
}

This is a static function to aid in constructing Note objects if we have a JSON string. In other words, fromJSON is a factory method. The difference is that JSON is associated with an instance...