But at a minimum, you license npm to provide Your Content to users of npm Services when you share Your Content.
There also seems to be no way to terminate this license:
Either you or npm may terminate this Agreement at any time with notice to the other.
On termination of this Agreement, your permission to use npm Open Source, as well any permission you may have to access Paid Services under additional terms, also terminate.
The following provisions survive termination of this Agreement: “Your Content”, “Feedback”, “Indemnity”, “Disclaimers”, “Limits on Liability”, and “General Terms”. Users of npm Services may continue to copy and share Your Content after termination of this Agreement.
So they’re very clear about this. You cannot force npmjs.com to stop distributing your code after you publish it.