semver

The semantic versioner for npm.

Usage

$ npm install semver

semver.valid('1.2.3') // true
semver.valid('a.b.c') // false
semver.clean('  =v1.2.3   ') // '1.2.3'
semver.satisfies('1.2.3', '1.x || >=2.5.0 || 5.0.0 - 7.2.3') // true
semver.gt('1.2.3', '9.8.7') // false
semver.lt('1.2.3', '9.8.7') // true

As a command-line utility:

$ semver -h

Usage: semver -v <version> [-r <range>]
Test if version(s) satisfy the supplied range(s),
and sort them.

Multiple versions or ranges may be supplied.

Program exits successfully if any valid version satisfies
all supplied ranges, and prints all satisfying versions.

If no versions are valid, or ranges are not satisfied,
then exits failure.

Versions are printed in ascending order, so supplying
multiple versions to the utility will just sort them.

Versions

A version is the following things, in this order:

• a number (Major)
• a period
• a number (minor)
• a period
• a number (patch)
• OPTIONAL: a hyphen, followed by a number (build)
• OPTIONAL: a collection of pretty much any non-whitespace characters (tag)

A leading "=" or "v" character is stripped off and ignored.

Comparisons

The ordering of versions is done using the following algorithm, given two versions and asked to find the greater of the two:

• If the majors are numerically different, then take the one with a bigger major number. 2.3.4 > 1.3.4
• If the minors are numerically different, then take the one with the bigger minor number. 2.3.4 > 2.2.4
• If the patches are numerically different, then take the one with the bigger patch number. 2.3.4 > 2.3.3
• If only one of them has a build number, then take the one with the build number. 2.3.4-0 > 2.3.4
• If they both have build numbers, and the build numbers are numerically different, then take the one with the bigger build number. 2.3.4-10 > 2.3.4-9
• If only one of them has a tag, then take the one without the tag. 2.3.4 > 2.3.4-beta
• If they both have tags, then take the one with the lexicographically larger tag. 2.3.4-beta > 2.3.4-alpha
• At this point, they're equal.

Ranges

The following range styles are supported:

• >1.2.3 Greater than a specific version.
• <1.2.3 Less than
• 1.2.3 - 2.3.4 := >=1.2.3 <=2.3.4
• ~1.2.3 := >=1.2.3 <1.3.0
• ~1.2 := >=1.2.0 <2.0.0
• ~1 := >=1.0.0 <2.0.0
• 1.2.x := >=1.2.0 <1.3.0
• 1.x := >=1.0.0 <2.0.0

Ranges can be joined with either a space (which implies "and") or a || (which implies "or").