I have a situation where I have an API version and my web frontend is aware of that version at application start. When doing live updates of the backend, I want to be able to decide which connections coming from frontend can be considered API stable with my backend (does this make sense?).

Example

1. Server runs version 0.1.2
2. User starts and thus now runs on version 0.1.2
3. Server application gets upgraded to 0.1.3
4. User interacts with server, but now there is a version mismatch.

In this case, I want to say 0.1.2 satisfies 0.1.x, so the APIs are compatible. Because all version information comes from variables here, I'm wondering how I should go about generating the 0.1.x range, or >=0.1.0 <0.2.0 range. To generate the latter I was thinking of this:

var version = '0.1.2';
var str = '>=' + semver.truncate(version, 'patch') + ' <' + semver.inc(version, 'minor');
// now do a satisfies check

The inc() method already exists, but truncate() does not. Do you think it would make sense to add a method like that?