PHP's version_compare in JavaScript

module.exports = functionversion_compare (v1, v2, operator) { // eslint-disable-line camelcase
//       discuss at: https://locutus.io/php/version_compare/
//      original by: Philippe Jausions (https://pear.php.net/user/jausions)
//      original by: Aidan Lister (https://aidanlister.com/)
// reimplemented by: Kankrelune (https://www.webfaktory.info/)
//      improved by: Brett Zamir (https://brett-zamir.me)
//      improved by: Scott Baker
//      improved by: Theriault (https://github.com/Theriault)
//        example 1: version_compare('8.2.5rc', '8.2.5a')
//        returns 1: 1
//        example 2: version_compare('8.2.50', '8.2.52', '<')
//        returns 2: true
//        example 3: version_compare('5.3.0-dev', '5.3.0')
//        returns 3: -1
//        example 4: version_compare('4.1.0.52','4.01.0.51')
//        returns 4: 1
// Important: compare must be initialized at 0.
let i
let x
let compare = 0
// vm maps textual PHP versions to negatives so they're less than 0.
// PHP currently defines these as CASE-SENSITIVE. It is important to
// leave these as negatives so that they can come before numerical versions
// and as if no letters were there to begin with.
// (1alpha is < 1 and < 1.1 but > 1dev1)
// If a non-numerical value can't be mapped to this table, it receives
// -7 as its value.
const vm = {
dev: -6,
alpha: -5,
a: -5,
beta: -4,
b: -4,
RC: -3,
rc: -3,
'#': -2,
p: 1,
pl: 1
  }
// This function will be called to prepare each version argument.
// It replaces every _, -, and + with a dot.
// It surrounds any nonsequence of numbers/dots with dots.
// It replaces sequences of dots with a single dot.
//    version_compare('4..0', '4.0') === 0
// Important: A string of 0 length needs to be converted into a value
// even less than an unexisting value in vm (-7), hence [-8].
// It's also important to not strip spaces because of this.
//   version_compare('', ' ') === 1
const _prepVersion = function (v) {
    v = ('' + v).replace(/[_\-+]/g, '.')
    v = v.replace(/([^.\d]+)/g, '.$1.').replace(/\.{2,}/g, '.')
return (!v.length ? [-8] : v.split('.'))
  }
// This converts a version component to a number.
// Empty component becomes 0.
// Non-numerical component becomes a negative number.
// Numerical component becomes itself as an integer.
const _numVersion = function (v) {
return !v ? 0 : (isNaN(v) ? vm[v] || -7 : parseInt(v, 10))
  }
  v1 = _prepVersion(v1)
  v2 = _prepVersion(v2)
  x = Math.max(v1.length, v2.length)
for (i = 0; i < x; i++) {
if (v1[i] === v2[i]) {
continue
    }
    v1[i] = _numVersion(v1[i])
    v2[i] = _numVersion(v2[i])
if (v1[i] < v2[i]) {
      compare = -1
break
    } elseif (v1[i] > v2[i]) {
      compare = 1
break
    }
  }
if (!operator) {
return compare
  }
// Important: operator is CASE-SENSITIVE.
// "No operator" seems to be treated as "<."
// Any other values seem to make the function return null.
switch (operator) {
case'>':
case'gt':
return (compare > 0)
case'>=':
case'ge':
return (compare >= 0)
case'<=':
case'le':
return (compare <= 0)
case'===':
case'=':
case'eq':
return (compare === 0)
case'<>':
case'!==':
case'ne':
return (compare !== 0)
case'':
case'<':
case'lt':
return (compare < 0)
default:
returnnull
  }
}