Unintuitive comparison result for lt(undefined, B)

[dfunckt]

lt(undefined, B) results in true and it seems that's expected: https://github.com/balena-io-modules/resin-semver/blob/master/test/index.spec.ts#L448

However I think the result is counter-intuitive and should really be false -- i.e. undefined should always result in false.

The current behaviour prevents writing code that only branches to handle legacy cases, eg.:

if (semver.lt(osVersion, '2.0.0')) {
  return doLegacy();
}
return doNormal();

The above must be written with the "happy path" inverted or check for undefined in the branch condition.

[dfunckt]

Even more counter-intuitive is that satisfies seems to work as expected: https://github.com/balena-io-modules/resin-semver/blob/master/test/index.spec.ts#L505

So the above could be written:

if (semver.satisfies(osVersion, '<2.0.0')) {
  return doLegacy();
}
return doNormal();