I need to say this because there’s too much moaning and grinding of teeth going on about npm packages loads of projects depend on.
If you have a project with dependencies, do yourself a favor and have an in-house mirror for those. It’s even more important if you’re a software shop which works primarily with one technology, which I presume is a very common case.
That way, when we “clean install” the last checked in code for final delivery into the QA and deployment teams, we don’t run into crazy issues like having it not build because someone decided to take their code down – or had it taken down by force.
In a Netflix chaos monkey-like approach, try to foresee and forestall all causes for unreliability at go time, not only with this but any other kind of externalized source of services. You, your family, significant others, pillow, boss, co-workers and customers will all be happier for it.