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version_compare

Here’s what our current JavaScript equivalent to PHP's version_compare looks like.

module.exports = function version_compare (v1, v2, operator) { // eslint-disable-line camelcase
  //       discuss at: http://locutus.io/php/version_compare/
  //      original by: Philippe Jausions (http://pear.php.net/user/jausions)
  //      original by: Aidan Lister (http://aidanlister.com/)
  // reimplemented by: Kankrelune (http://www.webfaktory.info/)
  //      improved by: Brett Zamir (http://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.
  var i
  var x
  var 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.
  var 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
  var _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.
  var _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
    } else if (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:
      return null
  }
}
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How to use

You you can install via npm install locutus and require it via require('locutus/php/info/version_compare'). You could also require the info module in full so that you could access info.version_compare instead.

If you intend to target the browser, you can then use a module bundler such as Browserify, webpack or rollup.js.

ES5/ES6

This function targets ES5, but as of Locutus 2.0.2 we also support ES6 functions. Locutus transpiles to ES5 before publishing to npm.

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we don't consider it to be a bad thing that many of our functions are first iterations, which may still have their fair share of issues. We hope that these flaws will inspire others to come up with better ideas.

This way of working also means that we don't offer any production guarantees, and recommend to use Locutus inspiration and learning purposes only.

Examples

Please note that these examples are distilled from test cases that automatically verify our functions still work correctly. This could explain some quirky ones.

#codeexpected result
1version_compare('8.2.5rc', '8.2.5a')1
2version_compare('8.2.50', '8.2.52', '<')true
3version_compare('5.3.0-dev', '5.3.0')-1
4version_compare('4.1.0.52','4.01.0.51')1
声明:转载请注明原文地址及作者姓名。 作者:Glary Joker 文章地址://glaryjoker.com/article/374.html
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