semver(1) – The semantic versioner for npm

Install

npm install semver
````

## 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.

## 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](https://github.com/npm/node-semver#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:

```javascript
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

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:

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        ::= parts
build      ::= parts
parts      ::= part ( '.' part ) *
part       ::= nr | [-0-9A-Za-z]+

Comparison

• gt(v1, v2): v1 > v2
• gte(v1, v2): v1 >= v2
• lt(v1, v2): v1 < v2
• lte(v1, v2): v1 <= v2
• eq(v1, v2): v1 == v2 This is true if they’re logically equivalent, even if they’re not the same string. You already know how to compare strings.
• neq(v1, v2): v1 != v2 The opposite of eq.
• cmp(v1, comparator, v2): Pass in a comparison string, and it’ll call the corresponding function above. "===" and "!==" do simple string comparison, but are included for completeness. Throws if an invalid comparison string is provided.
• compare(v1, v2): Return 0 if v1 == v2, or 1 if v1 is greater, or -1 if v2 is greater. Sorts in ascending order if passed to Array.sort().
• rcompare(v1, v2): The reverse of compare. Sorts an array of versions in descending order when passed to Array.sort().
• compareBuild(v1, v2): The same as compare but considers build when two versions are equal. Sorts in ascending order if passed to Array.sort().
• compareLoose(v1, v2): Short for compare(v1, v2, { loose: true }).
• diff(v1, v2): Returns the difference between two versions by the release type (major, premajor, minor, preminor, patch, prepatch, or prerelease), or null if the versions are the same.

Sorting

• sort(versions): Returns a sorted array of versions based on the compareBuild function.
• rsort(versions): The reverse of sort. Returns an array of versions based on the compareBuild function in descending order.

Comparators

• intersects(comparator): Return true if the comparators intersect

Ranges

• validRange(range): Return the valid range or null if it’s not valid
• satisfies(version, range): Return true if the version satisfies the range.
• maxSatisfying(versions, range): Return the highest version in the list that satisfies the range, or null if none of them do.
• minSatisfying(versions, range): Return the lowest version in the list that satisfies the range, or null if none of them do.
• minVersion(range): Return the lowest version that can match the given range.
• gtr(version, range): Return true if the version is greater than all the versions possible in the range.
• ltr(version, range): Return true if the version is less than all the versions possible in the range.
• outside(version, range, hilo): Return true if the version is outside the bounds of the range in either the high or low direction. The hilo argument must be either the string '>' or '<'. (This is the function called by gtr and ltr.)
• intersects(range): Return true if any of the range comparators intersect.
• simplifyRange(versions, range): Return a “simplified” range that matches the same items in the versions list as the range specified. Note that it does not guarantee that it would match the same versions in all cases, only for the set of versions provided. This is useful when generating ranges by joining together multiple versions with || programmatically, to provide the user with something a bit more ergonomic. If the provided range is shorter in string-length than the generated range, then that is returned.
• subset(subRange, superRange): Return true if the subRange range is entirely contained by the superRange range.

Note that, since ranges may be non-contiguous, a version might not be greater than a range, less than a range, or satisfy a range! For example, the range 1.2 <1.2.9 || >2.0.0 would have a hole from 1.2.9 until 2.0.0, so version 1.2.10 would not be greater than the range (because 2.0.1 satisfies, which is higher), nor less than the range (since 1.2.8 satisfies, which is lower), and it also does not satisfy the range.

If you want to know if a version satisfies or does not satisfy a range, use the satisfies(version, range) function.

Coercion

• coerce(version, options): Coerces a string to semver if possible

This aims to provide a very forgiving translation of a non-semver string to semver. It looks for the first digit in a string and consumes all remaining characters which satisfy at least a partial semver (e.g., 1, 1.2, 1.2.3) up to the max permitted length (256 characters). Longer versions are simply truncated (4.6.3.9.2-alpha2 becomes 4.6.3). All surrounding text is simply ignored (v3.4 replaces v3.3.1 becomes 3.4.0). Only text which lacks digits will fail coercion (version one is not valid). The maximum length for any semver component considered for coercion is 16 characters; longer components will be ignored (10000000000000000.4.7.4 becomes 4.7.4). The maximum value for any semver component is Number.MAX_SAFE_INTEGER || (2**53 - 1); higher value components are invalid (9999999999999999.4.7.4 is likely invalid).

If the options.rtl flag is set, then coerce will return the right-most coercible tuple that does not share an ending index with a longer coercible tuple. For example, 1.2.3.4 will return 2.3.4 in rtl mode, not 4.0.0. 1.2.3/4 will return 4.0.0, because the 4 is not a part of any other overlapping SemVer tuple.

If the options.includePrerelease flag is set, then the coerce result will contain prerelease and build parts of a version. For example, 1.2.3.4-rc.1+rev.2 will preserve prerelease rc.1 and build rev.2 in the result.

Clean

• clean(version): Clean a string to be a valid semver if possible

This will return a cleaned and trimmed semver version. If the provided version is not valid a null will be returned. This does not work for ranges.

ex.

• s.clean(' = v 2.1.5foo'): null
• s.clean(' = v 2.1.5foo', { loose: true }): '2.1.5-foo'
• s.clean(' = v 2.1.5-foo'): null
• s.clean(' = v 2.1.5-foo', { loose: true }): '2.1.5-foo'
• s.clean('=v2.1.5'): '2.1.5'
• s.clean(' =v2.1.5'): '2.1.5'
• s.clean(' 2.1.5 '): '2.1.5'
• s.clean('~1.0.0'): null

RELEASE_TYPES

• major
• premajor
• minor
• preminor
• patch
• prepatch
• prerelease

const semver = require('semver');

if (semver.RELEASE_TYPES.includes(arbitraryUserInput)) {
  console.log('This is a valid release type!');
} else {
  console.warn('This is NOT a valid release type!');
}

SEMVER_SPEC_VERSION

2.0.0

const semver = require('semver');

console.log('We are currently using the semver specification version:', semver.SEMVER_SPEC_VERSION);

Exported Modules

You may pull in just the part of this semver utility that you need if you are sensitive to packing and tree-shaking concerns. The main require('semver') export uses getter functions to lazily load the parts of the API that are used.

The following modules are available:

• require('semver')
• require('semver/classes')
• require('semver/classes/comparator')
• require('semver/classes/range')
• require('semver/classes/semver')
• require('semver/functions/clean')
• require('semver/functions/cmp')
• require('semver/functions/coerce')
• require('semver/functions/compare')
• require('semver/functions/compare-build')
• require('semver/functions/compare-loose')
• require('semver/functions/diff')
• require('semver/functions/eq')
• require('semver/functions/gt')
• require('semver/functions/gte')
• require('semver/functions/inc')
• require('semver/functions/lt')
• require('semver/functions/lte')
• require('semver/functions/major')
• require('semver/functions/minor')
• require('semver/functions/neq')
• require('semver/functions/parse')
• require('semver/functions/patch')
• require('semver/functions/prerelease')
• require('semver/functions/rcompare')
• require('semver/functions/rsort')
• require('semver/functions/satisfies')
• require('semver/functions/sort')
• require('semver/functions/valid')
• require('semver/ranges/gtr')
• require('semver/ranges/intersects')
• require('semver/ranges/ltr')
• require('semver/ranges/max-satisfying')
• require('semver/ranges/min-satisfying')
• require('semver/ranges/min-version')
• require('semver/ranges/outside')
• require('semver/ranges/simplify')
• require('semver/ranges/subset')
• require('semver/ranges/to-comparators')
• require('semver/ranges/valid')