HORIZON PROJECT

semver(1) -- The semantic versioner for npm

===========================================

## Install

```bash

npm install --save 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.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

SemVer 5.3.0

A JavaScript implementation of the http://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

-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.

```

## Versions

A "version" is described by the `v2.0.0` specification found at

<http://semver.org/>.

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

## Ranges

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`.

### 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.  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.

#### 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:

```bash

$ semver 1.2.3 -i prerelease --preid beta

1.2.4-beta.0

```

Which then can be used to increment further:

```bash

$ semver 1.2.4-beta.0 -i prerelease

1.2.4-beta.1

```

### 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`

* `1.2.3 - 2` := `>=1.2.3 <3.0.0`

#### 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 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) := `*` := `>=0.0.0`

* `1` := `1.x.x` := `>=1.0.0 <2.0.0`

* `1.2` := `1.2.x` := `>=1.2.0 <1.3.0`

#### 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`

* `~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.

#### Caret Ranges `^1.2.3` `^0.2.5` `^0.0.4`

Allows 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 <0.1.0`

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.x` := `>=0.0.0 <1.0.0`

### 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        ::= parts

build      ::= parts

parts      ::= part ( '.' part ) *

part       ::= nr | [-0-9A-Za-z]+

```

## Functions

All methods and classes take a final `loose` boolean argument that, if

true, will be more forgiving about not-quite-valid semver strings.

The resulting output will always be 100% strict, of course.

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.

  * If called from a non-prerelease version, the `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.

### 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 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.

### 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.

* `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 intersect

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 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.

### Coercion

* `coerce(version)`: 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 `Integer.MAX_SAFE_INTEGER || (2**53 - 1)`;

higher value components are invalid (`9999999999999999.4.7.4` is likely invalid).