Skip Unchanged files during build process

Hi, hope you well.

I have a Ionic 2 app that has grown big. Everytime I save (build), its rebuilding everything i.e. copying files even the ones which didnt change. This process is affecting perfomance badly as I have to wait for a min to view the changes and leads to a memory leak error. Is there a way I can use to restrict the build process from copying/building files that have not changed and copy/bulild only the ones which have changed?

How are you building the app exactly?

I am using this command: ionic serve