How to use assitant api to interact with component and feature of app

how to use assitant api to interact with component and feature of app(like wanderlust modify the map)

You might need to search for websocket servers.

A simple entry could be stream.io in nodejs.

what if for iOS development, any similar tech?

Where is the difference? You need to send data to the frontend where a javascript/piece of code is activated.

There are multiple technologies like websockets.