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Forked from TheDistantSea/version_compare.js
Created October 12, 2015 09:10
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Function to compare two version strings (e.g. "1.6.1" is smaller than "1.7"). Developed in order to answer http://stackoverflow.com/a/6832721/50079.
/**
* Compares two software version numbers (e.g. "1.7.1" or "1.2b").
*
* This function was born in http://stackoverflow.com/a/6832721.
*
* @param {string} v1 The first version to be compared.
* @param {string} v2 The second version to be compared.
* @param {object} [options] Optional flags that affect comparison behavior:
* <ul>
* <li>
* <tt>lexicographical: true</tt> compares each part of the version strings lexicographically instead of
* naturally; this allows suffixes such as "b" or "dev" but will cause "1.10" to be considered smaller than
* "1.2".
* </li>
* <li>
* <tt>zeroExtend: true</tt> changes the result if one version string has less parts than the other. In
* this case the shorter string will be padded with "zero" parts instead of being considered smaller.
* </li>
* </ul>
* @returns {number|NaN}
* <ul>
* <li>0 if the versions are equal</li>
* <li>a negative integer iff v1 < v2</li>
* <li>a positive integer iff v1 > v2</li>
* <li>NaN if either version string is in the wrong format</li>
* </ul>
*
* @copyright by Jon Papaioannou (["john", "papaioannou"].join(".") + "@gmail.com")
* @license This function is in the public domain. Do what you want with it, no strings attached.
*/
function versionCompare(v1, v2, options) {
var lexicographical = options && options.lexicographical,
zeroExtend = options && options.zeroExtend,
v1parts = v1.split('.'),
v2parts = v2.split('.');
function isValidPart(x) {
return (lexicographical ? /^\d+[A-Za-z]*$/ : /^\d+$/).test(x);
}
if (!v1parts.every(isValidPart) || !v2parts.every(isValidPart)) {
return NaN;
}
if (zeroExtend) {
while (v1parts.length < v2parts.length) v1parts.push("0");
while (v2parts.length < v1parts.length) v2parts.push("0");
}
if (!lexicographical) {
v1parts = v1parts.map(Number);
v2parts = v2parts.map(Number);
}
for (var i = 0; i < v1parts.length; ++i) {
if (v2parts.length == i) {
return 1;
}
if (v1parts[i] == v2parts[i]) {
continue;
}
else if (v1parts[i] > v2parts[i]) {
return 1;
}
else {
return -1;
}
}
if (v1parts.length != v2parts.length) {
return -1;
}
return 0;
}
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