Ionic cli not working after December 2019

I have a project working with ionic v4. It worked well with compilation well 22th December. After I am back from my vacation, it doesn’t work now. I cannot run “ionic serve”. Then I reinstalled angular and get error “You seem to not be depending on “@angular/core” and/or “rxjs””.
Then I remade another project and I can run “ionic serve” but not “ionic build”.
Has any of you got such problem?