Typescript compiler not run when invoking npm i from packages/app-mobile

So the title says it all really.

Is it by design?
I have spent a few hours trying to understand why my changes to one of .ts files in packages/app-mobile had no effect. Turns out it's because I was only running npm i from app-mobile, not from the root.

The build system has changed since the move to Lerna so if you haven't already, it's best to check the new BUILD.md file: joplin/BUILD.md at docker_server_update · laurent22/joplin · GitHub

In a nutshell, you now need to run npm i from the root of the project, then npm run watch to watch for TypeScript file changes.