The semver package is a module for semantic versioning (semver) parsing and comparison. It provides utilities for working with semantic version numbers, allowing users to parse, compare, increment, and manipulate version numbers according to the semantic versioning specification.
Parsing and Validating Versions
This feature allows you to parse a version string and check if it is a valid semantic version.
"const semver = require('semver');
const version = '1.2.3';
const valid = semver.valid(version); // '1.2.3'"Comparing Versions
This feature enables you to compare two semantic version numbers to determine their order.
"const semver = require('semver');
const v1 = '1.2.3';
const v2 = '4.5.6';
const comparison = semver.compare(v1, v2); // -1"Incrementing Versions
This feature allows you to increment a version number by the major, minor, or patch version.
"const semver = require('semver');
const version = '1.2.3';
const incremented = semver.inc(version, 'patch'); // '1.2.4'"Ranges and Satisfaction
This feature checks if a version satisfies a given range.
"const semver = require('semver');
const version = '1.2.3';
const range = '^1.0.0';
const satisfied = semver.satisfies(version, range); // true"Coercion
This feature coerces a string to a semantic version if possible.
"const semver = require('semver');
const version = 'v1';
const coerced = semver.coerce(version); // '1.0.0'"This package provides a simple way to compare version numbers. While semver offers a full suite of semantic versioning features, compare-versions focuses solely on the comparison aspect, making it a lighter alternative for this specific use case.
This is an alternative package that also implements the semantic versioning specification. It is similar to semver but may have different APIs or additional features.
This package is used to validate version numbers against the semantic versioning specification. Unlike semver, which offers a broad range of versioning utilities, validate-version is specifically tailored for validation.
npm install --save semver
As a node module:
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'
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, or prerelease. 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
-p --include-prerelease
Always include prerelease versions in range matching
-c --coerce
Coerce a string into SemVer if possible
(does not imply --loose)
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.
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.
A version range is a set of comparators which 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.
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.
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. The
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 for 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 clearly 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 the purpose of range
matching) by setting the includePrerelease flag on the options
object to any
functions that do
range matching.
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
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 ||.
X.Y.Z - A.B.CSpecifies an inclusive set.
1.2.3 - 2.3.4 := >=1.2.3 <=2.3.4If 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 <=2.3.4If 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 <2.4.01.2.3 - 2 := >=1.2.3 <3.0.01.2.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 version satisfies)1.x := >=1.0.0 <2.0.0 (Matching major version)1.2.x := >=1.2.0 <1.3.0 (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) := * := >=0.0.01 := 1.x.x := >=1.0.0 <2.0.01.2 := 1.2.x := >=1.2.0 <1.3.0~1.2.3 ~1.2 ~1Allows 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 <1.3.0~1.2 := >=1.2.0 <1.(2+1).0 := >=1.2.0 <1.3.0 (Same as 1.2.x)~1 := >=1.0.0 <(1+1).0.0 := >=1.0.0 <2.0.0 (Same as 1.x)~0.2.3 := >=0.2.3 <0.(2+1).0 := >=0.2.3 <0.3.0~0.2 := >=0.2.0 <0.(2+1).0 := >=0.2.0 <0.3.0 (Same as 0.2.x)~0 := >=0.0.0 <(0+1).0.0 := >=0.0.0 <1.0.0 (Same as 0.x)~1.2.3-beta.2 := >=1.2.3-beta.2 <1.3.0 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.^1.2.3 ^0.2.5 ^0.0.4Allows changes that do not modify the left-most non-zero digit 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 <2.0.0^0.2.3 := >=0.2.3 <0.3.0^0.0.3 := >=0.0.3 <0.0.4^1.2.3-beta.2 := >=1.2.3-beta.2 <2.0.0 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 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.x := >=0.0.0 <0.1.0^0.0 := >=0.0.0 <0.1.0A 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.x := >=0.0.0 <1.0.0Putting 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]+
All methods and classes take a final options object argument. All
options in this object are false by default. The options supported
are:
loose Be more forgiving about not-quite-valid semver strings.
(Any resulting output will always be 100% strict compliant, of
course.) For backwards compatibility reasons, if the options
argument is a boolean value instead of an object, it is interpreted
to be the loose param.includePrerelease Set to suppress the default
behavior of
excluding prerelease tagged versions from ranges unless they are
explicitly opted into.Strict-mode Comparators and Ranges will be strict about the SemVer strings that they parse.
valid(v): Return the parsed version, or null if it's not valid.inc(v, release): Return the version incremented by the release
type (major, premajor, minor, preminor, patch,
prepatch, or prerelease), or null if it's not valid
premajor in one call will bump the version up to the next major
version and down to a prerelease of that major version.
preminor, and prepatch work the same way.prerelease will work the
same as prepatch. It increments the patch version, then makes a
prerelease. If the input version is already a prerelease it simply
increments it.prerelease(v): Returns an array of prerelease components, or null
if none exist. Example: prerelease('1.2.3-alpha.1') -> ['alpha', 1]major(v): Return the major version number.minor(v): Return the minor version number.patch(v): Return the patch version number.intersects(r1, r2, loose): Return true if the two supplied ranges
or comparators intersect.parse(v): Attempt to parse a string as a semantic version, returning either
a SemVer object or null.gt(v1, v2): v1 > v2gte(v1, v2): v1 >= v2lt(v1, v2): v1 < v2lte(v1, v2): v1 <= v2eq(v1, v2): v1 == v2 This is true if they're logically equivalent,
even if they're not the exact 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().diff(v1, v2): Returns difference between two versions by the release type
(major, premajor, minor, preminor, patch, prepatch, or prerelease),
or null if the versions are the same.intersects(comparator): Return true if the comparators intersectvalidRange(range): Return the valid range or null if it's not validsatisfies(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 possibly match
the given range.gtr(version, range): Return true if version is greater than all the
versions possible in the range.ltr(version, range): Return true if 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 ranges comparators intersectNote 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 the 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.
coerce(version): Coerces a string to semver if possibleThis 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).
FAQs
The semantic version parser used by npm.
The npm package semver receives a total of 63,833,713 weekly downloads. As such, semver popularity was classified as popular.
We found that semver demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 5 open source maintainers collaborating on the project.
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