This repo shows an improved version of solution for a test task. Not sure I managed to recall everything what was requested though.
Main improvement is a fix for debounced promise. Also I had to implement some backend to make it work.
Simple React + Typescript frontend. Builds with Webpack, via yarn build.
Contains a single index.tsx file.
Python Aiohttp server, which serves static index.min.js, which is built from client folder.
This is borrowed from my previous project, so some unnecessary complications are present, like logging and templates folder.
The server exposes an api/items endpoint, which actually filters a list of cities by substring, passed over in a q parameter. No error handling and no edge case checks is present.