tag-cmp

Compare two semver-like version strings, returning -1, 0, or 1.

This can be used with Array.sort.

Example

var {cmpTags} = require('tag-cmp');

cmpTags("1.2b1", "1.2") === -1;

arr = ["1.2b1", "1.11", "1.2"];
arr.sort(cmpTags) === ["1.2b1", "1.2", "1.11"];

Version precedence

Versions are being compared in natural sort order (i.e. lexicographic with the consideration of multi-digit numbers), with a special exception for "pre-release identifiers" (letters that immediately follow a number).

Example in ascending order:

• v1.3 (goes first just because others don't have the "v")
• 1.1.2 (lowest minor version)
• 1.2rc1 (precedes the following as a "release candidate" of 1.2)
• 1.2 (actual release)
• 1.2.1 (patch release)
• 1.11 (much later version; 11 > 2 even if '1' < '2')

(and so 1.11 would be chosen as the "greatest").

This handling is compatible with SemVer, but more general.

There is no attempt to isolate the version number from other text that may be part of the tag name. But that's not a problem if the tags have a matching prefix, e.g. Release-1.2.3 and Release-1.2.4. But, Foo-3.4.5 would precede these just because 'F' < 'R'.