[RRFC] New command for detecting availability of a package name

Motivation ("The Why")

It's kind of impossible to know if a package name is available without trying to publish a package with that name. As a result sometimes it's very frustrating to develop a new package, because once you are done NPM tells you that the name is already taken, often with an obscure error message, and you need to find another one.

Example

For example, NPM tells me that the ansi-strip package doesn't exit (https://www.npmjs.com/package/ansi-strip), but then I try to publish it and it tells me "npm ERR! 400 Bad Request - PUT https://registry.npmjs.org/ansi-strip - Cannot publish over previously published version "1.0.0", as if the package exists (I guess it's a private one or something?), and as if I've already published v1.

How

Current Behaviour

Frustration.

Desired Behaviour

Something like npm available ansi-strip that tells you if you can publish a new package with that name or not.

References

• n/a

No repository files, tests, or entry points are named. Start by reviewing the proposed npm available <name> behavior and the npm registry example; done would be an accepted RFC that specifies how package-name availability and the reported errors should be determined.