If it can be done with native code (iOS and android) then you could also write a native extension to launch an app. However, because mobile apps are installed in individual sandboxes apps probably have no way of telling the parent OS to list current apps or run a paticular app. This is just my opionion from what I have understood so far. I think you can create some sort of native extension and use the following methods below.
Have a look here:
As for iOS you would need to use App urls which would be application specific.