SemVer Parser

Parse, verify, compare SemVer.

Install

npm install semver-parser

API

APIs can be used either synchronously or asynchronously. Async function returns Promise which resolves with the result.

sync:

import { compareSemVer, isValidSemVer, parseSemVer } from 'semver-parser';

async:

import { promises } from 'semver-parser';
const { compareSemVer, isValidSemVer, parseSemVer } = promises;

NOTE: Is "v1.2.3" a semantic version?

Is "v1.2.3" a semantic version?

No, "v1.2.3" is not a semantic version. However, prefixing a semantic version with a "v" is a common way (in English) to indicate it is a version number.

For ease of use, this parser supports "v" prefixed string. If you do not want to accept "v" prefix, set strict param to true.

parseSemVer(version, strict)

Parses version string.

• @param {string} version - version string
• @param {boolean} [strict] - reject 'v' prefixed
• @returns {Object} - parsed result, contains properties below
  • version {string} - given version string
  • matches {boolean} - matches SemVer format
  • major {number|undefined} - major version
  • minor {number|undefined} - minor version
  • patch {number|undefined} - patch version
  • pre {Array<string|number>|undefined} - pre release version in array
  • build {Array<string|number>|undefined} - build ID in array

isValidSemVer(version, strict)

Determine whether the given argument is a valid SemVer string.

• @param {string} version - version string
• @param {boolean} [strict] - reject 'v' prefixed
• @returns {boolean} - result

compareSemVer(version, base, strict)

Compare versions in SemVer format.

• @param {string} version - version string
• @param {string} base - base version string to compare from
• @param {boolean} [strict] - reject 'v' prefixed
• @returns {number}
  • -1 or negative number, if version is less than base version
  • 0, if version is equal to base version
  • 1 or positive number, if version is greater than base version

Backus–Naur Form Grammar for Valid SemVer Versions to JavaScript RegExp

valid semver

<valid semver> ::= <version core>
                 | <version core> "-" <pre-release>
                 | <version core> "+" <build>
                 | <version core> "-" <pre-release> "+" <build>

(?:0|[1-9]\d*)(?:\.(?:0|[1-9]\d*)){2}(?:-(?:0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*)(?:\.(?:0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*))*)?(?:\+(?:\d*[A-Za-z-][\dA-Za-z-]*|\d+)(?:\.(?:\d*[A-Za-z-][\dA-Za-z-]*|\d+))*)?

version core

<version core> ::= <major> "." <minor> "." <patch>

(?:0|[1-9]\d*)(?:\.(?:0|[1-9]\d*)){2}

major

<major> ::= <numeric identifier>

0|[1-9]\d*

minor

<minor> ::= <numeric identifier>

0|[1-9]\d*

patch

<patch> ::= <numeric identifier>

0|[1-9]\d*

pre-release

<pre-release> ::= <dot-separated pre-release identifiers>

(?:0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*)(?:\.(?:0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*))*

dot-separated pre-release identifiers

<dot-separated pre-release identifiers> ::= <pre-release identifier>
                                          | <pre-release identifier> "." <dot-separated pre-release identifiers>

(?:0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*)(?:\.(?:0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*))*

build

<build> ::= <dot-separated build identifiers>

(?:\d*[A-Za-z-][\dA-Za-z-]*|\d+)(?:\.(?:\d*[A-Za-z-][\dA-Za-z-]*|\d+))*

dot-separated build identifiers

<dot-separated build identifiers> ::= <build identifier>
                                    | <build identifier> "." <dot-separated build identifiers>

(?:\d*[A-Za-z-][\dA-Za-z-]*|\d+)(?:\.(?:\d*[A-Za-z-][\dA-Za-z-]*|\d+))*

pre-release identifier

<pre-release identifier> ::= <alphanumeric identifier>
                           | <numeric identifier>

0|[1-9]\d*|\d*[A-Za-z-][\dA-Za-z-]*

build identifier

<build identifier> ::= <alphanumeric identifier>
                     | <digits>

\d*[A-Za-z-][\dA-Za-z-]*|\d+

alphanumeric identifier

<alphanumeric identifier> ::= <non-digit>
                            | <non-digit> <identifier characters>
                            | <identifier characters> <non-digit>
                            | <identifier characters> <non-digit> <identifier characters>

[\dA-Za-z-]*[A-Za-z-][\dA-Za-z-]*

optimized:

\d*[A-Za-z-][\dA-Za-z-]*

numeric identifier

<numeric identifier> ::= "0"
                       | <positive digit>
                       | <positive digit> <digits>

0|[1-9]\d*

identifier characters

<identifier characters> ::= <identifier character>
                          | <identifier character> <identifier characters>

[\dA-Za-z-]+

identifier character

<identifier character> ::= <digit>
                         | <non-digit>

[\dA-Za-z-]

non-digit

<non-digit> ::= <letter>
              | "-"

[A-Za-z-]

digits

<digits> ::= <digit>
           | <digit> <digits>

\d+

digit

<digit> ::= "0"
          | <positive digit>

\d

positive digit

<positive digit> ::= "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"

[1-9]

letter

<letter> ::= "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J"
           | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T"
           | "U" | "V" | "W" | "X" | "Y" | "Z" | "a" | "b" | "c" | "d"
           | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m" | "n"
           | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x"
           | "y" | "z"

[A-Za-z]