[BUG] Invalid falsey response when checking range is subset of any

[jameschensmith]

What / Why

I've run into an interesting issue when submitting a PR for npm's arborist library, where a range (e.g. ~3.5.0) is not a subset of any. This should be supported, as even though any is not a subset of a range (which is already handled), the opposite is not the case.

I think the fix would be to add an additional short-circuit check in lines 58-62 (v7.3.4 snippet) to handle an any dom value:

  if (sub === dom)
    return true

+  if (dom.length === 1 && dom[0].semver === ANY)
+    return true

  if (sub.length === 1 && sub[0].semver === ANY)
    return dom.length === 1 && dom[0].semver === ANY

When

I run a subset comparison for if a given range is a subset of any

Example

const semver = require("semver");
// ~3.5.0 := >=3.5.0 <3.(5+1).0 := >=3.5.0 <3.6.0-0
console.log(semver.subset("~3.5.0", "*"));
// false

Current Behavior

Result is falsey.

Expected Behavior

Result should be truthy, as >=3.5.0 <3.6.0-0 should be a subset of any.

References

• [BUG] (CLI-related) npm install ignores explicit prefix arborist#253 (this comment).