node-version-compare/index.js

a node module to compare semver version

'use strict';

function compare(v1, v2) {
  v1 = v1 + '';
  v2 = v2 + '';

  var flag1 = v1.indexOf('-') > -1;
  var flag2 = v2.indexOf('-') > -1;
  var arr1 = split(flag1, v1);
  var arr2 = split(flag2, v2);
  arr1 = convertToNumber(arr1);
  arr2 = convertToNumber(arr2);
  var len = Math.max(arr1.length, arr2.length);
  for (var i = 0; i < len; i++) {
    // 1.0.0 > 1.0.0-beta.2
    if (i === 3 && (arr1[i] === undefined || arr2[i] === undefined)) {
      if (arr1[i] === undefined && isNaN(arr2[i])) {
        return 1;
      } else {
        if (isNaN(arr1[i]) && arr2[i] === undefined) {
          return -1;
        }
      }
    }
    if (arr1[i] === undefined) {
      return -1;
    } else {
      if (arr2[i] === undefined) {
        return 1;
      }
    }
    if (arr1[i] > arr2[i]) {
      return 1;
    } else {
      if (arr1[i] < arr2[i]) {
        return -1;
      }
    }
  }
  return 0;
}

function split(flag, version) {
  version = version + '';

  var result = [];
  if (flag) {
    var tail = version.split('-')[1];
    var _version = version.split('-')[0];
    result = _version.split('.');
    tail = tail.split('.');
    result = result.concat(tail);
  } else {
    result = version.split('.');
  }
  return result;
}

function convertToNumber(arr) {
  return arr.map(function (el) {
    return isNaN(el) ? el : parseInt(el);
  });
}

module.exports = compare;