basic implementation of "similar notes" widget

src/routes/api/similar_notes.js

@@ -0,0 +1,24 @@
+"use strict";
+
+const noteCacheService = require('../../services/note_cache');
+const repository = require('../../services/repository');
+
+async function getSimilarNotes(req) {
+    const noteId = req.params.noteId;
+
+    const note = await repository.getNote(noteId);
+
+    if (!note) {
+        return [404, `Note ${noteId} not found.`];
+    }
+
+    const results = await noteCacheService.findNotes(note.title);
+
+    return results
+        .map(r => r.noteId)
+        .filter(similarNoteId => similarNoteId !== noteId);
+}
+
+module.exports = {
+    getSimilarNotes
+};