semver

The semver module provides functions to work with semantic version strings.

Semantic version strings are in the form:

vMAJOR[.MINOR[.PATCH[-PRERELEASE][+BUILD]]]

The square brackets indicate optional fields with the string.

The MAJOR, MINOR, and PATCH strings must be decimal integers without leading zeros. The PRERELEASE and BUILD strings may contain alphanumeric identifiers and hyphens. If the PRERELEASE string is numeric, it must not have leading zeros.

This implementation matches Semver version 2 (opens in a new tab) with two exceptions:

1. The version string must begin with a leading "v".
2. The MINOR and PATCH fields are optional and default to 0 if not specified.

The core functionality is provided by golang.org/x/mod/semver (opens in a new tab).

Functions

build

build(v string) string

Returns the build metadata of the specified version string.

>>> semver.build("v1.2.3+build234")
"+build234"

canonical

canonical(v string) string

Returns the canonical formatting of the semantic version string. The function fills in any missing minor or patch fields with zeros and removes any build metadata.

>>> semver.canonical("v1")
"v1.0.0"

compare

compare(v1, v2 string) int

Compares two version strings and returns -1, 0, or 1 if v1 is less than, equal to, or greater than v2, respectively.

>>> semver.compare("v1.2.3", "v1.2.4")
-1

is_valid

is_valid(v string) bool

Returns true if the specified version string is a valid semantic version.

>>> semver.is_valid("v1.2.3")
true
>>> semver.is_valid("3")
false

major

major(v string) string

Returns the major version of the specified version string.

>>> semver.major("v1.2.3")
"v1"

major_minor

major_minor(v string) string

Returns the major and minor version of the specified version string.

>>> semver.major_minor("v1.2.3")
"v1.2"

prerelease

prerelease(v string) string

Returns the prerelease information of the specified version string.

>>> semver.prerelease("v1.2.3-alpha")
"alpha"