Stopped

1. Navigate to project root path
2. Run npm i
3. Run npm run start

Note. Make sure that you have MongoDB installed and running.

Express.js is server-side Node.js framework running along with MongoDB as NoSQL database. Mongoose is used as ORM layer for manipulating database documents. Server-side app is connected with client via WebSockets with help of socket.io.

Client-side is a SPA with immutable app state stored in Redux Store. State is managed by action creators and reducer. React is used as presentation layer framework.

Geographical map is created and managed by ArcGIS JS API.

Mocha is used as a BDD framework to describe specifications along with chai testing utilities.

Project is written in JavaScript with benefits of ECMAScript 6 standard provided by Babel. Webpack is used as project bundler along with server middleware dev tools such as React Hot Loader and hot module replacement.

Styles are preprocessed by Less.

Lazy loading of spots is made in a primitive way. Each time map bounds is changed (map has been moved or zoomed), a socket.io-request is made to a server. Bunch of received spots are being compared to existing ones and if there is something new, spots are re-rendered.

This may be optimized in different ways:

• Using tile-based loader: map view is split into a number of small square "tiles" and separate request is made for each tile. This enables use of browser cache.
• Using complex multi-polygon area as sum of loaded bounds and subtract it out of current bounds before making request.
• Using ArcGIS Map Service or ArcGIS Feature Service.
• Using another cartographical API (i.e. Yandex.Maps Remote Object Manager).