semver(1) -- The semantic versioner for npm

Install

npm install semver
````

## Usage

As a node module:

```js
const semver = require('semver')

semver.valid('1.2.3') // '1.2.3'
semver.valid('a.b.c') // null
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
semver.minVersion('>=1.0.0') // '1.0.0'
semver.valid(semver.coerce('v2')) // '2.0.0'
semver.valid(semver.coerce('42.6.7.9.3-alpha')) // '42.6.7'

You can also just load the module for the function that you care about if you'd like to minimize your footprint.

// load the whole API at once in a single object
const semver = require('semver')

// or just load the bits you need
// all of them listed here, just pick and choose what you want

// classes
const SemVer = require('semver/classes/semver')
const Comparator = require('semver/classes/comparator')
const Range = require('semver/classes/range')

// functions for working with versions
const semverParse = require('semver/functions/parse')
const semverValid = require('semver/functions/valid')
const semverClean = require('semver/functions/clean')
const semverInc = require('semver/functions/inc')
const semverDiff = require('semver/functions/diff')
const semverMajor = require('semver/functions/major')
const semverMinor = require('semver/functions/minor')
const semverPatch = require('semver/functions/patch')
const semverPrerelease = require('semver/functions/prerelease')
const semverCompare = require('semver/functions/compare')
const semverRcompare = require('semver/functions/rcompare')
const semverCompareLoose = require('semver/functions/compare-loose')
const semverCompareBuild = require('semver/functions/compare-build')
const semverSort = require('semver/functions/sort')
const semverRsort = require('semver/functions/rsort')
const semverTruncate = require('semver/functions/truncate')

// low-level comparators between versions
const semverGt = require('semver/functions/gt')
const semverLt = require('semver/functions/lt')
const semverEq = require('semver/functions/eq')
const semverNeq = require('semver/functions/neq')
const semverGte = require('semver/functions/gte')
const semverLte = require('semver/functions/lte')
const semverCmp = require('semver/functions/cmp')
const semverCoerce = require('semver/functions/coerce')

// working with ranges
const semverSatisfies = require('semver/functions/satisfies')
const semverMaxSatisfying = require('semver/ranges/max-satisfying')
const semverMinSatisfying = require('semver/ranges/min-satisfying')
const semverToComparators = require('semver/ranges/to-comparators')
const semverMinVersion = require('semver/ranges/min-version')
const semverValidRange = require('semver/ranges/valid')
const semverOutside = require('semver/ranges/outside')
const semverGtr = require('semver/ranges/gtr')
const semverLtr = require('semver/ranges/ltr')
const semverIntersects = require('semver/ranges/intersects')
const semverSimplifyRange = require('semver/ranges/simplify')
const semverRangeSubset = require('semver/ranges/subset')

As a command-line utility:

$ semver -h

A JavaScript implementation of the https://semver.org/ specification
Copyright Isaac Z. Schlueter

Usage: semver [options] <version> [<version> [...]]
Prints valid versions sorted by SemVer precedence

Options:
-r --range <range>
        Print versions that match the specified range.

-i --increment [<level>]
        Increment a version by the specified level.  Level can
        be one of: major, minor, patch, premajor, preminor,
        prepatch, prerelease, or release.  Default level is 'patch'.
        Only one version may be specified.

--preid <identifier>
        Identifier to be used to prefix premajor, preminor,
        prepatch or prerelease version increments.

-l --loose
        Interpret versions and ranges loosely

-n <0|1|false>
        Base number for prerelease identifier (default: 0).
        Use false to omit the number altogether.

-p --include-prerelease
        Always include prerelease versions in range matching

-c --coerce
        Coerce a string into SemVer if possible
        (does not imply --loose)

--rtl
        Coerce version strings right to left

--ltr
        Coerce version strings left to right (default)

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

If no satisfying versions are found, then exits failure.

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

Versions

A "version" is described by the v2.0.0 specification found at https://semver.org/.

A leading "=" or "v" character is stripped off and ignored. Support for stripping a leading "v" is kept for compatibility with v1.0.0 of the SemVer specification but should not be used anymore.

Ranges

A version range is a set of comparators that specify versions that satisfy the range.

A comparator is composed of an operator and a version. The set of primitive operators is:

• < Less than
• <= Less than or equal to
• > Greater than
• >= Greater than or equal to
• = Equal. If no operator is specified, then equality is assumed, so this operator is optional but MAY be included.

For example, the comparator >=1.2.7 would match the versions 1.2.7, 1.2.8, 2.5.3, and 1.3.9, but not the versions 1.2.6 or 1.1.0. The comparator >1 is equivalent to >=2.0.0 and would match the versions 2.0.0 and 3.1.0, but not the versions 1.0.1 or 1.1.0.

Comparators can be joined by whitespace to form a comparator set, which is satisfied by the intersection of all of the comparators it includes.

A range is composed of one or more comparator sets, joined by ||. A version matches a range if and only if every comparator in at least one of the ||-separated comparator sets is satisfied by the version.

For example, the range >=1.2.7 <1.3.0 would match the versions 1.2.7, 1.2.8, and 1.2.99, but not the versions 1.2.6, 1.3.0, or 1.1.0.

The range 1.2.7 || >=1.2.9 <2.0.0 would match the versions 1.2.7, 1.2.9, and 1.4.6, but not the versions 1.2.8 or 2.0.0.

Prerelease Tags

If a version has a prerelease tag (for example, 1.2.3-alpha.3) then it will only be allowed to satisfy comparator sets if at least one comparator with the same [major, minor, patch] tuple also has a prerelease tag.

For example, the range >1.2.3-alpha.3 would be allowed to match the version 1.2.3-alpha.7, but it would not be satisfied by 3.4.5-alpha.9, even though 3.4.5-alpha.9 is technically "greater than" 1.2.3-alpha.3 according to the SemVer sort rules. The version range only accepts prerelease tags on the 1.2.3 version. Version 3.4.5 would satisfy the range because it does not have a prerelease flag, and 3.4.5 is greater than 1.2.3-alpha.7.

The purpose of this behavior is twofold. First, prerelease versions frequently are updated very quickly, and contain many breaking changes that are (by the author's design) not yet fit for public consumption. Therefore, by default, they are excluded from range-matching semantics.

Second, a user who has opted into using a prerelease version has indicated the intent to use that specific set of alpha/beta/rc versions. By including a prerelease tag in the range, the user is indicating that they are aware of the risk. However, it is still not appropriate to assume that they have opted into taking a similar risk on the next set of prerelease versions.

Note that this behavior can be suppressed (treating all prerelease versions as if they were normal versions, for range-matching) by setting the includePrerelease flag on the options object to any functions that do range matching.

Prerelease Identifiers

The method .inc takes an additional identifier string argument that will append the value of the string as a prerelease identifier:

semver.inc('1.2.3', 'prerelease', 'beta')
// '1.2.4-beta.0'

command-line example:

$ semver 1.2.3 -i prerelease --preid beta
1.2.4-beta.0

Which then can be used to increment further:

$ semver 1.2.4-beta.0 -i prerelease
1.2.4-beta.1

To get out of the prerelease phase, use the release option:

$ semver 1.2.4-beta.1 -i release
1.2.4

Prerelease Identifier Base

The method .inc takes an optional parameter 'identifierBase' string that will let you let your prerelease number as zero-based or one-based. Set to false to omit the prerelease number altogether. If you do not specify this parameter, it will default to zero-based.

semver.inc('1.2.3', 'prerelease', 'beta', '1')
// '1.2.4-beta.1'

semver.inc('1.2.3', 'prerelease', 'beta', false)
// '1.2.4-beta'

command-line example:

$ semver 1.2.3 -i prerelease --preid beta -n 1
1.2.4-beta.1

$ semver 1.2.3 -i prerelease --preid beta -n false
1.2.4-beta

Advanced Range Syntax

Advanced range syntax desugars to primitive comparators in deterministic ways.

Advanced ranges may be combined in the same way as primitive comparators using white space or ||.

Hyphen Ranges X.Y.Z - A.B.C

Specifies an inclusive set.

• 1.2.3 - 2.3.4 := >=1.2.3 <=2.3.4

If a partial version is provided as the first version in the inclusive range, then the missing pieces are replaced with zeroes.

• 1.2 - 2.3.4 := >=1.2.0 <=2.3.4

If a partial version is provided as the second version in the inclusive range, then all versions that start with the supplied parts of the tuple are accepted, but nothing that would be greater than the provided tuple parts.

• 1.2.3 - 2.3 := >=1.2.3 <2.4.0-0
• 1.2.3 - 2 := >=1.2.3 <3.0.0-0

X-Ranges 1.2.x 1.X 1.2.* *

Any of X, x, or * may be used to "stand in" for one of the numeric values in the [major, minor, patch] tuple.

• * := >=0.0.0 (Any non-prerelease version satisfies, unless includePrerelease is specified, in which case any version at all satisfies)
• 1.x := >=1.0.0 <2.0.0-0 (Matching major version)
• 1.2.x := >=1.2.0 <1.3.0-0 (Matching major and minor versions)

A partial version range is treated as an X-Range, so the special character is in fact optional.

• "" (empty string) := * := >=0.0.0
• 1 := 1.x.x := >=1.0.0 <2.0.0-0
• 1.2 := 1.2.x := >=1.2.0 <1.3.0-0

Tilde Ranges ~1.2.3 ~1.2 ~1

Allows patch-level changes if a minor version is specified on the comparator. Allows minor-level changes if not.

• ~1.2.3 := >=1.2.3 <1.(2+1).0 := >=1.2.3 <1.3.0-0
• ~1.2 := >=1.2.0 <1.(2+1).0 := >=1.2.0 <1.3.0-0 (Same as 1.2.x)
• ~1 := >=1.0.0 <(1+1).0.0 := >=1.0.0 <2.0.0-0 (Same as 1.x)
• ~0.2.3 := >=0.2.3 <0.(2+1).0 := >=0.2.3 <0.3.0-0
• ~0.2 := >=0.2.0 <0.(2+1).0 := >=0.2.0 <0.3.0-0 (Same as 0.2.x)
• ~0 := >=0.0.0 <(0+1).0.0 := >=0.0.0 <1.0.0-0 (Same as 0.x)
• ~1.2.3-beta.2 := >=1.2.3-beta.2 <1.3.0-0 Note that prereleases in the 1.2.3 version will be allowed, if they are greater than or equal to beta.2. So, 1.2.3-beta.4 would be allowed, but 1.2.4-beta.2 would not, because it is a prerelease of a different [major, minor, patch] tuple.

Caret Ranges ^1.2.3 ^0.2.5 ^0.0.4

Allows changes that do not modify the left-most non-zero element in the [major, minor, patch] tuple. In other words, this allows patch and minor updates for versions 1.0.0 and above, patch updates for versions 0.X >=0.1.0, and no updates for versions 0.0.X.

Many authors treat a 0.x version as if the x were the major "breaking-change" indicator.

Caret ranges are ideal when an author may make breaking changes between 0.2.4 and 0.3.0 releases, which is a common practice. However, it presumes that there will not be breaking changes between 0.2.4 and 0.2.5. It allows for changes that are presumed to be additive (but non-breaking), according to commonly observed practices.

• ^1.2.3 := >=1.2.3 <2.0.0-0
• ^0.2.3 := >=0.2.3 <0.3.0-0
• ^0.0.3 := >=0.0.3 <0.0.4-0
• ^1.2.3-beta.2 := >=1.2.3-beta.2 <2.0.0-0 Note that prereleases in the 1.2.3 version will be allowed, if they are greater than or equal to beta.2. So, 1.2.3-beta.4 would be allowed, but 1.2.4-beta.2 would not, because it is a prerelease of a different [major, minor, patch] tuple.
• ^0.0.3-beta := >=0.0.3-beta <0.0.4-0 Note that prereleases in the 0.0.3 version only will be allowed, if they are greater than or equal to beta. So, 0.0.3-pr.2 would be allowed.

When parsing caret ranges, a missing patch value desugars to the number 0, but will allow flexibility within that value, even if the major and minor versions are both 0.

• ^1.2.x := >=1.2.0 <2.0.0-0
• ^0.0.x := >=0.0.0 <0.1.0-0
• ^0.0 := >=0.0.0 <0.1.0-0

A missing minor and patch values will desugar to zero, but also allow flexibility within those values, even if the major version is zero.

• ^1.x := >=1.0.0 <2.0.0-0
• ^0.x := >=0.0.0 <1.0.0-0

Range Grammar

Putting all this together, here is a Backus-Naur grammar for ranges, for the benefit of parser authors:

```bnf range-set ::= range ( logical-or range ) * logical-or ::= ( ' ' ) * '||' ( ' ' ) * range ::= hyphen | simple ( ' ' simple ) * | '' hyphen ::= partial ' - ' partial simple ::= primitive | partial | tilde | caret primitive ::= ( '<' | '>' | '>=' | '<=' | '=' ) partial partial ::= xr ( '.' xr ( '.' xr qualifier ? )? )? xr ::= 'x' | 'X' | '*' | nr nr ::= '0' | ['1'-'9'] ( ['0'-'9'] ) * tilde ::= '~' partial caret ::= '^' partial qualifier ::= ( '-' pre )? ( '+' build )? pre ::= prepart ( '.' prepart ) * pre