notes/node_modules/semver/semver.js

exports = module.exports = SemVer;

// The debug function is excluded entirely from the minified version.
/* nomin */ var debug;
/* nomin */ if (typeof process === 'object' &&
    /* nomin */ process.env &&
    /* nomin */ process.env.NODE_DEBUG &&
    /* nomin */ /\bsemver\b/i.test(process.env.NODE_DEBUG))
  /* nomin */ debug = function() {
    /* nomin */ var args = Array.prototype.slice.call(arguments, 0);
    /* nomin */ args.unshift('SEMVER');
    /* nomin */ console.log.apply(console, args);
    /* nomin */ };
/* nomin */ else
  /* nomin */ debug = function() {};

// Note: this is the semver.org version of the spec that it implements
// Not necessarily the package version of this code.
exports.SEMVER_SPEC_VERSION = '2.0.0';

var MAX_LENGTH = 256;
var MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER || 9007199254740991;

// The actual regexps go on exports.re
var re = exports.re = [];
var src = exports.src = [];
var R = 0;

// The following Regular Expressions can be used for tokenizing,
// validating, and parsing SemVer version strings.

// ## Numeric Identifier
// A single `0`, or a non-zero digit followed by zero or more digits.

var NUMERICIDENTIFIER = R++;
src[NUMERICIDENTIFIER] = '0|[1-9]\\d*';
var NUMERICIDENTIFIERLOOSE = R++;
src[NUMERICIDENTIFIERLOOSE] = '[0-9]+';


// ## Non-numeric Identifier
// Zero or more digits, followed by a letter or hyphen, and then zero or
// more letters, digits, or hyphens.

var NONNUMERICIDENTIFIER = R++;
src[NONNUMERICIDENTIFIER] = '\\d*[a-zA-Z-][a-zA-Z0-9-]*';


// ## Main Version
// Three dot-separated numeric identifiers.

var MAINVERSION = R++;
src[MAINVERSION] = '(' + src[NUMERICIDENTIFIER] + ')\\.' +
                   '(' + src[NUMERICIDENTIFIER] + ')\\.' +
                   '(' + src[NUMERICIDENTIFIER] + ')';

var MAINVERSIONLOOSE = R++;
src[MAINVERSIONLOOSE] = '(' + src[NUMERICIDENTIFIERLOOSE] + ')\\.' +
                        '(' + src[NUMERICIDENTIFIERLOOSE] + ')\\.' +
                        '(' + src[NUMERICIDENTIFIERLOOSE] + ')';

// ## Pre-release Version Identifier
// A numeric identifier, or a non-numeric identifier.

var PRERELEASEIDENTIFIER = R++;
src[PRERELEASEIDENTIFIER] = '(?:' + src[NUMERICIDENTIFIER] +
                            '|' + src[NONNUMERICIDENTIFIER] + ')';

var PRERELEASEIDENTIFIERLOOSE = R++;
src[PRERELEASEIDENTIFIERLOOSE] = '(?:' + src[NUMERICIDENTIFIERLOOSE] +
                                 '|' + src[NONNUMERICIDENTIFIER] + ')';


// ## Pre-release Version
// Hyphen, followed by one or more dot-separated pre-release version
// identifiers.

var PRERELEASE = R++;
src[PRERELEASE] = '(?:-(' + src[PRERELEASEIDENTIFIER] +
                  '(?:\\.' + src[PRERELEASEIDENTIFIER] + ')*))';

var PRERELEASELOOSE = R++;
src[PRERELEASELOOSE] = '(?:-?(' + src[PRERELEASEIDENTIFIERLOOSE] +
                       '(?:\\.' + src[PRERELEASEIDENTIFIERLOOSE] + ')*))';

// ## Build Metadata Identifier
// Any combination of digits, letters, or hyphens.

var BUILDIDENTIFIER = R++;
src[BUILDIDENTIFIER] = '[0-9A-Za-z-]+';

// ## Build Metadata
// Plus sign, followed by one or more period-separated build metadata
// identifiers.

var BUILD = R++;
src[BUILD] = '(?:\\+(' + src[BUILDIDENTIFIER] +
             '(?:\\.' + src[BUILDIDENTIFIER] + ')*))';


// ## Full Version String
// A main version, followed optionally by a pre-release version and
// build metadata.

// Note that the only major, minor, patch, and pre-release sections of
// the version string are capturing groups.  The build metadata is not a
// capturing group, because it should not ever be used in version
// comparison.

var FULL = R++;
var FULLPLAIN = 'v?' + src[MAINVERSION] +
                src[PRERELEASE] + '?' +
                src[BUILD] + '?';

src[FULL] = '^' + FULLPLAIN + '$';

// like full, but allows v1.2.3 and =1.2.3, which people do sometimes.
// also, 1.0.0alpha1 (prerelease without the hyphen) which is pretty
// common in the npm registry.
var LOOSEPLAIN = '[v=\\s]*' + src[MAINVERSIONLOOSE] +
                 src[PRERELEASELOOSE] + '?' +
                 src[BUILD] + '?';

var LOOSE = R++;
src[LOOSE] = '^' + LOOSEPLAIN + '$';

var GTLT = R++;
src[GTLT] = '((?:<|>)?=?)';

// Something like "2.*" or "1.2.x".
// Note that "x.x" is a valid xRange identifer, meaning "any version"
// Only the first item is strictly required.
var XRANGEIDENTIFIERLOOSE = R++;
src[XRANGEIDENTIFIERLOOSE] = src[NUMERICIDENTIFIERLOOSE] + '|x|X|\\*';
var XRANGEIDENTIFIER = R++;
src[XRANGEIDENTIFIER] = src[NUMERICIDENTIFIER] + '|x|X|\\*';

var XRANGEPLAIN = R++;
src[XRANGEPLAIN] = '[v=\\s]*(' + src[XRANGEIDENTIFIER] + ')' +
                   '(?:\\.(' + src[XRANGEIDENTIFIER] + ')' +
                   '(?:\\.(' + src[XRANGEIDENTIFIER] + ')' +
                   '(?:' + src[PRERELEASE] + ')?' +
                   src[BUILD] + '?' +
                   ')?)?';

var XRANGEPLAINLOOSE = R++;
src[XRANGEPLAINLOOSE] = '[v=\\s]*(' + src[XRANGEIDENTIFIERLOOSE] + ')' +
                        '(?:\\.(' + src[XRANGEIDENTIFIERLOOSE] + ')' +
                        '(?:\\.(' + src[XRANGEIDENTIFIERLOOSE] + ')' +
                        '(?:' + src[PRERELEASELOOSE] + ')?' +
                        src[BUILD] + '?' +
                        ')?)?';

var XRANGE = R++;
src[XRANGE] = '^' + src[GTLT] + '\\s*' + src[XRANGEPLAIN] + '$';
var XRANGELOOSE = R++;
src[XRANGELOOSE] = '^' + src[GTLT] + '\\s*' + src[XRANGEPLAINLOOSE] + '$';

// Tilde ranges.
// Meaning is "reasonably at or greater than"
var LONETILDE = R++;
src[LONETILDE] = '(?:~>?)';

var TILDETRIM = R++;
src[TILDETRIM] = '(\\s*)' + src[LONETILDE] + '\\s+';
re[TILDETRIM] = new RegExp(src[TILDETRIM], 'g');
var tildeTrimReplace = '$1~';

var TILDE = R++;
src[TILDE] = '^' + src[LONETILDE] + src[XRANGEPLAIN] + '$';
var TILDELOOSE = R++;
src[TILDELOOSE] = '^' + src[LONETILDE] + src[XRANGEPLAINLOOSE] + '$';

// Caret ranges.
// Meaning is "at least and backwards compatible with"
var LONECARET = R++;
src[LONECARET] = '(?:\\^)';

var CARETTRIM = R++;
src[CARETTRIM] = '(\\s*)' + src[LONECARET] + '\\s+';
re[CARETTRIM] = new RegExp(src[CARETTRIM], 'g');
var caretTrimReplace = '$1^';

var CARET = R++;
src[CARET] = '^' + src[LONECARET] + src[XRANGEPLAIN] + '$';
var CARETLOOSE = R++;
src[CARETLOOSE] = '^' + src[LONECARET] + src[XRANGEPLAINLOOSE] + '$';

// A simple gt/lt/eq thing, or just "" to indicate "any version"
var COMPARATORLOOSE = R++;
src[COMPARATORLOOSE] = '^' + src[GTLT] + '\\s*(' + LOOSEPLAIN + ')$|^$';
var COMPARATOR = R++;
src[COMPARATOR] = '^' + src[GTLT] + '\\s*(' + FULLPLAIN + ')$|^$';


// An expression to strip any whitespace between the gtlt and the thing
// it modifies, so that `> 1.2.3` ==> `>1.2.3`
var COMPARATORTRIM = R++;
src[COMPARATORTRIM] = '(\\s*)' + src[GTLT] +
                      '\\s*(' + LOOSEPLAIN + '|' + src[XRANGEPLAIN] + ')';

// this one has to use the /g flag
re[COMPARATORTRIM] = new RegExp(src[COMPARATORTRIM], 'g');
var comparatorTrimReplace = '$1$2$3';


// Something like `1.2.3 - 1.2.4`
// Note that these all use the loose form, because they'll be
// checked against either the strict or loose comparator form
// later.
var HYPHENRANGE = R++;
src[HYPHENRANGE] = '^\\s*(' + src[XRANGEPLAIN] + ')' +
                   '\\s+-\\s+' +
                   '(' + src[XRANGEPLAIN] + ')' +
                   '\\s*$';

var HYPHENRANGELOOSE = R++;
src[HYPHENRANGELOOSE] = '^\\s*(' + src[XRANGEPLAINLOOSE] + ')' +
                        '\\s+-\\s+' +
                        '(' + src[XRANGEPLAINLOOSE] + ')' +
                        '\\s*$';

// Star ranges basically just allow anything at all.
var STAR = R++;
src[STAR] = '(<|>)?=?\\s*\\*';

// Compile to actual regexp objects.
// All are flag-free, unless they were created above with a flag.
for (var i = 0; i < R; i++) {
  debug(i, src[i]);
  if (!re[i])
    re[i] = new RegExp(src[i]);
}

exports.parse = parse;
function parse(version, loose) {
  if (version instanceof SemVer)
    return version;

  if (typeof version !== 'string')
    return null;

  if (version.length > MAX_LENGTH)
    return null;

  var r = loose ? re[LOOSE] : re[FULL];
  if (!r.test(version))
    return null;

  try {
    return new SemVer(version, loose);
  } catch (er) {
    return null;
  }
}

exports.valid = valid;
function valid(version, loose) {
  var v = parse(version, loose);
  return v ? v.version : null;
}


exports.clean = clean;
function clean(version, loose) {
  var s = parse(version.trim().replace(/^[=v]+/, ''), loose);
  return s ? s.version : null;
}

exports.SemVer = SemVer;

function SemVer(version, loose) {
  if (version instanceof SemVer) {
    if (version.loose === loose)
      return version;
    else
      version = version.version;
  } else if (typeof version !== 'string') {
    throw new TypeError('Invalid Version: ' + version);
  }

  if (version.length > MAX_LENGTH)
    throw new TypeError('version is longer than ' + MAX_LENGTH + ' characters')

  if (!(this instanceof SemVer))
    return new SemVer(version, loose);

  debug('SemVer', version, loose);
  this.loose = loose;
  var m = version.trim().match(loose ? re[LOOSE] : re[FULL]);

  if (!m)
    throw new TypeError('Invalid Version: ' + version);

  this.raw = version;

  // these are actually numbers
  this.major = +m[1];
  this.minor = +m[2];
  this.patch = +m[3];

  if (this.major > MAX_SAFE_INTEGER || this.major < 0)
    throw new TypeError('Invalid major version')

  if (this.minor > MAX_SAFE_INTEGER || this.minor < 0)
    throw new TypeError('Invalid minor version')

  if (this.patch > MAX_SAFE_INTEGER || this.patch < 0)
    throw new TypeError('Invalid patch version')

  // numberify any prerelease numeric ids
  if (!m[4])
    this.prerelease = [];
  else
    this.prerelease = m[4].split('.').map(function(id) {
      if (/^[0-9]+$/.test(id)) {
        var num = +id;
        if (num >= 0 && num < MAX_SAFE_INTEGER)
          return num;
      }
      return id;
    });

  this.build = m[5] ? m[5].split('.') : [];
  this.format();
}

SemVer.prototype.format = function() {
  this.version = this.major + '.' + this.minor + '.' + this.patch;
  if (this.prerelease.length)
    this.version += '-' + this.prerelease.join('.');
  return this.version;
};

SemVer.prototype.toString = function() {
  return this.version;
};

SemVer.prototype.compare = function(other) {
  debug('SemVer.compare', this.version, this.loose, other);
  if (!(other instanceof SemVer))
    other = new SemVer(other, this.loose);

  return this.compareMain(other) || this.comparePre(other);
};

SemVer.prototype.compareMain = function(other) {
  if (!(other instanceof SemVer))
    other = new SemVer(other, this.loose);

  return compareIdentifiers(this.major, other.major) ||
         compareIdentifiers(this.minor, other.minor) ||
         compareIdentifiers(this.patch, other.patch);
};

SemVer.prototype.comparePre = function(other) {
  if (!(other instanceof SemVer))
    other = new SemVer(other, this.loose);

  // NOT having a prerelease is > having one
  if (this.prerelease.length && !other.prerelease.length)
    return -1;
  else if (!this.prerelease.length && other.prerelease.length)
    return 1;
  else if (!this.prerelease.length && !other.prerelease.length)
    return 0;

  var i = 0;
  do {
    var a = this.prerelease[i];
    var b = other.prerelease[i];
    debug('prerelease compare', i, a, b);
    if (a === undefined && b === undefined)
      return 0;
    else if (b === undefined)
      return 1;
    else if (a === undefined)
      return -1;
    else if (a === b)
      continue;
    else
      return compareIdentifiers(a, b);
  } while (++i);
};

// preminor will bump the version up to the next minor release, and immediately
// down to pre-release. premajor and prepatch work the same way.
SemVer.prototype.inc = function(release, identifier) {
  switch (release) {
    case 'premajor':
      this.prerelease.length = 0;
      this.patch = 0;
      this.minor = 0;
      this.major++;
      this.inc('pre', identifier);
      break;
    case 'preminor':
      this.prerelease.length = 0;
      this.patch = 0;
      this.minor++;
      this.inc('pre', identifier);
      break;
    case 'prepatch':
      // If this is already a prerelease, it will bump to the next version
      // drop any prereleases that might already exist, since they are not
      // relevant at this point.
      this.prerelease.length = 0;
      this.inc('patch', identifier);
      this.inc('pre', identifier);
      break;
    // If the input is a non-prerelease version, this acts the same as
    // prepatch.
    case 'prerelease':
      if (this.prerelease.length === 0)
        this.inc('patch', identifier);
      this.inc('pre', identifier);
      break;

    case 'major':
      // If this is a pre-major version, bump up to the same major version.
      // Otherwise increment major.
      // 1.0.0-5 bumps to 1.0.0
      // 1.1.0 bumps to 2.0.0
      if (this.minor !== 0 || this.patch !== 0 || this.prerelease.length === 0)
        this.major++;
      this.minor = 0;
      this.patch = 0;
      this.prerelease = [];
      break;
    case 'minor':
      // If this is a pre-minor version, bump up to the same minor version.
      // Otherwise increment minor.
      // 1.2.0-5 bumps to 1.2.0
      // 1.2.1 bumps to 1.3.0
      if (this.patch !== 0 || this.prerelease.length === 0)
        this.minor++;
      this.patch = 0;
      this.prerelease = [];
      break;
    case 'patch':
      // If this is not a pre-release version, it will increment the patch.
      // If it is a pre-release it will bump up to the same patch version.
      // 1.2.0-5 patches to 1.2.0
      // 1.2.0 patches to 1.2.1
      if (this.prerelease.length === 0)
        this.patch++;
      this.prerelease = [];
      break;
    // This probably shouldn't be used publicly.
    // 1.0.0 "pre" would become 1.0.0-0 which is the wrong direction.
    case 'pre':
      if (this.prerelease.length === 0)
        this.prerelease = [0];
      else {
        var i = this.prerelease.length;
        while (--i >= 0) {
          if (typeof this.prerelease[i] === 'number') {
            this.prerelease[i]++;
            i = -2;
          }
        }
        if (i === -1) // didn't increment anything
          this.prerelease.push(0);
      }
      if (identifier) {
        // 1.2.0-beta.1 bumps to 1.2.0-beta.2,
        // 1.2.0-beta.fooblz or 1.2.0-beta bumps to 1.2.0-beta.0
        if (this.prerelease[0] === identifier) {
          if (isNaN(this.prerelease[1]))
            this.prerelease = [identifier, 0];
        } else
          this.prerelease = [identifier, 0];
      }
      break;

    default:
      throw new Error('invalid increment argument: ' + release);
  }
  this.format();
  this.raw = this.version;
  return this;
};

exports.inc = inc;
function inc(version, release, loose, identifier) {
  if (typeof(loose) === 'string') {
    identifier = loose;
    loose = undefined;
  }

  try {
    return new SemVer(version, loose).inc(release, identifier).version;
  } catch (er) {
    return null;
  }
}

exports.diff = diff;
function diff(version1, version2) {
  if (eq(version1, version2)) {
    return null;
  } else {
    var v1 = parse(version1);
    var v2 = parse(version2);
    if (v1.prerelease.length || v2.prerelease.length) {
      for (var key in v1) {
        if (key === 'major' || key === 'minor' || key === 'patch') {
          if (v1[key] !== v2[key]) {
            return 'pre'+key;
          }
        }
      }
      return 'prerelease';
    }
    for (var key in v1) {
      if (key === 'major' || key === 'minor' || key === 'patch') {
        if (v1[key] !== v2[key]) {
          return key;
        }
      }
    }
  }
}

exports.compareIdentifiers = compareIdentifiers;

var numeric = /^[0-9]+$/;
function compareIdentifiers(a, b) {
  var anum = numeric.test(a);
  var bnum = numeric.test(b);

  if (anum && bnum) {
    a = +a;
    b = +b;
  }

  return (anum && !bnum) ? -1 :
         (bnum && !anum) ? 1 :
         a < b ? -1 :
         a > b ? 1 :
         0;
}

exports.rcompareIdentifiers = rcompareIdentifiers;
function rcompareIdentifiers(a, b) {
  return compareIdentifiers(b, a);
}

exports.major = major;
function major(a, loose) {
  return new SemVer(a, loose).major;
}

exports.minor = minor;
function minor(a, loose) {
  return new SemVer(a, loose).minor;
}

exports.patch = patch;
function patch(a, loose) {
  return new SemVer(a, loose).patch;
}

exports.compare = compare;
function compare(a, b, loose) {
  return new SemVer(a, loose).compare(b);
}

exports.compareLoose = compareLoose;
function compareLoose(a, b) {
  return compare(a, b, true);
}

exports.rcompare = rcompare;
function rcompare(a, b, loose) {
  return compare(b, a, loose);
}

exports.sort = sort;
function sort(list, loose) {
  return list.sort(function(a, b) {
    return exports.compare(a, b, loose);
  });
}

exports.rsort = rsort;
function rsort(list, loose) {
  return list.sort(function(a, b) {
    return exports.rcompare(a, b, loose);
  });
}

exports.gt = gt;
function gt(a, b, loose) {
  return compare(a, b, loose) > 0;
}

exports.lt = lt;
function lt(a, b, loose) {
  return compare(a, b, loose) < 0;
}

exports.eq = eq;
function eq(a, b, loose) {
  return compare(a, b, loose) === 0;
}

exports.neq = neq;
function neq(a, b, loose) {
  return compare(a, b, loose) !== 0;
}

exports.gte = gte;
function gte(a, b, loose) {
  return compare(a, b, loose) >= 0;
}

exports.lte = lte;
function lte(a, b, loose) {
  return compare(a, b, loose) <= 0;
}

exports.cmp = cmp;
function cmp(a, op, b, loose) {
  var ret;
  switch (op) {
    case '===':
      if (typeof a === 'object') a = a.version;
      if (typeof b === 'object') b = b.version;
      ret = a === b;
      break;
    case '!==':
      if (typeof a === 'object') a = a.version;
      if (typeof b === 'object') b = b.version;
      ret = a !== b;
      break;
    case '': case '=': case '==': ret = eq(a, b, loose); break;
    case '!=': ret = neq(a, b, loose); break;
    case '>': ret = gt(a, b, loose); break;
    case '>=': ret = gte(a, b, loose); break;
    case '<': ret = lt(a, b, loose); break;
    case '<=': ret = lte(a, b, loose); break;
    default: throw new TypeError('Invalid operator: ' + op);
  }
  return ret;
}

exports.Comparator = Comparator;
function Comparator(comp, loose) {
  if (comp instanceof Comparator) {
    if (comp.loose === loose)
      return comp;
    else
      comp = comp.value;
  }

  if (!(this instanceof Comparator))
    return new Comparator(comp, loose);

  debug('comparator', comp, loose);
  this.loose = loose;
  this.parse(comp);

  if (this.semver === ANY)
    this.value = '';
  else
    this.value = this.operator + this.semver.version;

  debug('comp', this);
}

var ANY = {};
Comparator.prototype.parse = function(comp) {
  var r = this.loose ? re[COMPARATORLOOSE] : re[COMPARATOR];
  var m = comp.match(r);

  if (!m)
    throw new TypeError('Invalid comparator: ' + comp);

  this.operator = m[1];
  if (this.operator === '=')
    this.operator = '';

  // if it literally is just '>' or '' then allow anything.
  if (!m[2])
    this.semver = ANY;
  else
    this.semver = new SemVer(m[2], this.loose);
};

Comparator.prototype.toString = function() {
  return this.value;
};

Comparator.prototype.test = function(version) {
  debug('Comparator.test', version, this.loose);

  if (this.semver === ANY)
    return true;

  if (typeof version === 'string')
    version = new SemVer(version, this.loose);

  return cmp(version, this.operator, this.semver, this.loose);
};


exports.Range = Range;
function Range(range, loose) {
  if ((range instanceof Range) && range.loose === loose)
    return range;

  if (!(this instanceof Range))
    return new Range(range, loose);

  this.loose = loose;

  // First, split based on boolean or ||
  this.raw = range;
  this.set = range.split(/\s*\|\|\s*/).map(function(range) {
    return this.parseRange(range.trim());
  }, this).filter(function(c) {
    // throw out any that are not relevant for whatever reason
    return c.length;
  });

  if (!this.set.length) {
    throw new TypeError('Invalid SemVer Range: ' + range);
  }

  this.format();
}

Range.prototype.format = function() {
  this.range = this.set.map(function(comps) {
    return comps.join(' ').trim();
  }).join('||').trim();
  return this.range;
};

Range.prototype.toString = function() {
  return this.range;
};

Range.prototype.parseRange = function(range) {
  var loose = this.loose;
  range = range.trim();
  debug('range', range, loose);
  // `1.2.3 - 1.2.4` => `>=1.2.3 <=1.2.4`
  var hr = loose ? re[HYPHENRANGELOOSE] : re[HYPHENRANGE];
  range = range.replace(hr, hyphenReplace);
  debug('hyphen replace', range);
  // `> 1.2.3 < 1.2.5` => `>1.2.3 <1.2.5`
  range = range.replace(re[COMPARATORTRIM], comparatorTrimReplace);
  debug('comparator trim', range, re[COMPARATORTRIM]);

  // `~ 1.2.3` => `~1.2.3`
  range = range.replace(re[TILDETRIM], tildeTrimReplace);

  // `^ 1.2.3` => `^1.2.3`
  range = range.replace(re[CARETTRIM], caretTrimReplace);

  // normalize spaces
  range = range.split(/\s+/).join(' ');

  // At this point, the range is completely trimmed and
  // ready to be split into comparators.

  var compRe = loose ? re[COMPARATORLOOSE] : re[COMPARATOR];
  var set = range.split(' ').map(function(comp) {
    return parseComparator(comp, loose);
  }).join(' ').split(/\s+/);
  if (this.loose) {
    // in loose mode, throw out any that are not valid comparators
    set = set.filter(function(comp) {
      return !!comp.match(compRe);
    });
  }
  set = set.map(function(comp) {
    return new Comparator(comp, loose);
  });

  return set;
};

// Mostly just for testing and legacy API reasons
exports.toComparators = toComparators;
function toComparators(range, loose) {
  return new Range(range, loose).set.map(function(comp) {
    return comp.map(function(c) {
      return c.value;
    }).join(' ').trim().split(' ');
  });
}

// comprised of xranges, tildes, stars, and gtlt's at this point.
// already replaced the hyphen ranges
// turn into a set of JUST comparators.
function parseComparator(comp, loose) {
  debug('comp', comp);
  comp = replaceCarets(comp, loose);
  debug('caret', comp);
  comp = replaceTildes(comp, loose);
  debug('tildes', comp);
  comp = replaceXRanges(comp, loose);
  debug('xrange', comp);
  comp = replaceStars(comp, loose);
  debug('stars', comp);
  return comp;
}

function isX(id) {
  return !id || id.toLowerCase() === 'x' || id === '*';
}

// ~, ~> --> * (any, kinda silly)
// ~2, ~2.x, ~2.x.x, ~>2, ~>2.x ~>2.x.x --> >=2.0.0 <3.0.0
// ~2.0, ~2.0.x, ~>2.0, ~>2.0.x --> >=2.0.0 <2.1.0
// ~1.2, ~1.2.x, ~>1.2, ~>1.2.x --> >=1.2.0 <1.3.0
// ~1.2.3, ~>1.2.3 --> >=1.2.3 <1.3.0
// ~1.2.0, ~>1.2.0 --> >=1.2.0 <1.3.0
function replaceTildes(comp, loose) {
  return comp.trim().split(/\s+/).map(function(comp) {
    return replaceTilde(comp, loose);
  }).join(' ');
}

function replaceTilde(comp, loose) {
  var r = loose ? re[TILDELOOSE] : re[TILDE];
  return comp.replace(r, function(_, M, m, p, pr) {
    debug('tilde', comp, _, M, m, p, pr);
    var ret;

    if (isX(M))
      ret = '';
    else if (isX(m))
      ret = '>=' + M + '.0.0 <' + (+M + 1) + '.0.0';
    else if (isX(p))
      // ~1.2 == >=1.2.0 <1.3.0
      ret = '>=' + M + '.' + m + '.0 <' + M + '.' + (+m + 1) + '.0';
    else if (pr) {
      debug('replaceTilde pr', pr);
      if (pr.charAt(0) !== '-')
        pr = '-' + pr;
      ret = '>=' + M + '.' + m + '.' + p + pr +
            ' <' + M + '.' + (+m + 1) + '.0';
    } else
      // ~1.2.3 == >=1.2.3 <1.3.0
      ret = '>=' + M + '.' + m + '.' + p +
            ' <' + M + '.' + (+m + 1) + '.0';

    debug('tilde return', ret);
    return ret;
  });
}

// ^ --> * (any, kinda silly)
// ^2, ^2.x, ^2.x.x --> >=2.0.0 <3.0.0
// ^2.0, ^2.0.x --> >=2.0.0 <3.0.0
// ^1.2, ^1.2.x --> >=1.2.0 <2.0.0
// ^1.2.3 --> >=1.2.3 <2.0.0
// ^1.2.0 --> >=1.2.0 <2.0.0
function replaceCarets(comp, loose) {
  return comp.trim().split(/\s+/).map(function(comp) {
    return replaceCaret(comp, loose);
  }).join(' ');
}

function replaceCaret(comp, loose) {
  debug('caret', comp, loose);
  var r = loose ? re[CARETLOOSE] : re[CARET];
  return comp.replace(r, function(_, M, m, p, pr) {
    debug('caret', comp, _, M, m, p, pr);
    var ret;

    if (isX(M))
      ret = '';
    else if (isX(m))
      ret = '>=' + M + '.0.0 <' + (+M + 1) + '.0.0';
    else if (isX(p)) {
      if (M === '0')
        ret = '>=' + M + '.' + m + '.0 <' + M + '.' + (+m + 1) + '.0';
      else
        ret = '>=' + M + '.' + m + '.0 <' + (+M + 1) + '.0.0';
    } else if (pr) {
      debug('replaceCaret pr', pr);
      if (pr.charAt(0) !== '-')
        pr = '-' + pr;
      if (M === '0') {
        if (m === '0')
          ret = '>=' + M + '.' + m + '.' + p + pr +
                ' <' + M + '.' + m + '.' + (+p + 1);
        else
          ret = '>=' + M + '.' + m + '.' + p + pr +
                ' <' + M + '.' + (+m + 1) + '.0';
      } else
        ret = '>=' + M + '.' + m + '.' + p + pr +
              ' <' + (+M + 1) + '.0.0';
    } else {
      debug('no pr');
      if (M === '0') {
        if (m === '0')
          ret = '>=' + M + '.' + m + '.' + p +
                ' <' + M + '.' + m + '.' + (+p + 1);
        else
          ret = '>=' + M + '.' + m + '.' + p +
                ' <' + M + '.' + (+m + 1) + '.0';
      } else
        ret = '>=' + M + '.' + m + '.' + p +
              ' <' + (+M + 1) + '.0.0';
    }

    debug('caret return', ret);
    return ret;
  });
}

function replaceXRanges(comp, loose) {
  debug('replaceXRanges', comp, loose);
  return comp.split(/\s+/).map(function(comp) {
    return replaceXRange(comp, loose);
  }).join(' ');
}

function replaceXRange(comp, loose) {
  comp = comp.trim();
  var r = loose ? re[XRANGELOOSE] : re[XRANGE];
  return comp.replace(r, function(ret, gtlt, M, m, p, pr) {
    debug('xRange', comp, ret, gtlt, M, m, p, pr);
    var xM = isX(M);
    var xm = xM || isX(m);
    var xp = xm || isX(p);
    var anyX = xp;

    if (gtlt === '=' && anyX)
      gtlt = '';

    if (xM) {
      if (gtlt === '>' || gtlt === '<') {
        // nothing is allowed
        ret = '<0.0.0';
      } else {
        // nothing is forbidden
        ret = '*';
      }
    } else if (gtlt && anyX) {
      // replace X with 0
      if (xm)
        m = 0;
      if (xp)
        p = 0;

      if (gtlt === '>') {
        // >1 => >=2.0.0
        // >1.2 => >=1.3.0
        // >1.2.3 => >= 1.2.4
        gtlt = '>=';
        if (xm) {
          M = +M + 1;
          m = 0;
          p = 0;
        } else if (xp) {
          m = +m + 1;
          p = 0;
        }
      } else if (gtlt === '<=') {
        // <=0.7.x is actually <0.8.0, since any 0.7.x should
        // pass.  Similarly, <=7.x is actually <8.0.0, etc.
        gtlt = '<';
        if (xm)
          M = +M + 1;
        else
          m = +m + 1;
      }

      ret = gtlt + M + '.' + m + '.' + p;
    } else if (xm) {
      ret = '>=' + M + '.0.0 <' + (+M + 1) + '.0.0';
    } else if (xp) {
      ret = '>=' + M + '.' + m + '.0 <' + M + '.' + (+m + 1) + '.0';
    }

    debug('xRange return', ret);

    return ret;
  });
}

// Because * is AND-ed with everything else in the comparator,
// and '' means "any version", just remove the *s entirely.
function replaceStars(comp, loose) {
  debug('replaceStars', comp, loose);
  // Looseness is ignored here.  star is always as loose as it gets!
  return comp.trim().replace(re[STAR], '');
}

// This function is passed to string.replace(re[HYPHENRANGE])
// M, m, patch, prerelease, build
// 1.2 - 3.4.5 => >=1.2.0 <=3.4.5
// 1.2.3 - 3.4 => >=1.2.0 <3.5.0 Any 3.4.x will do
// 1.2 - 3.4 => >=1.2.0 <3.5.0
function hyphenReplace($0,
                       from, fM, fm, fp, fpr, fb,
                       to, tM, tm, tp, tpr, tb) {

  if (isX(fM))
    from = '';
  else if (isX(fm))
    from = '>=' + fM + '.0.0';
  else if (isX(fp))
    from = '>=' + fM + '.' + fm + '.0';
  else
    from = '>=' + from;

  if (isX(tM))
    to = '';
  else if (isX(tm))
    to = '<' + (+tM + 1) + '.0.0';
  else if (isX(tp))
    to = '<' + tM + '.' + (+tm + 1) + '.0';
  else if (tpr)
    to = '<=' + tM + '.' + tm + '.' + tp + '-' + tpr;
  else
    to = '<=' + to;

  return (from + ' ' + to).trim();
}


// if ANY of the sets match ALL of its comparators, then pass
Range.prototype.test = function(version) {
  if (!version)
    return false;

  if (typeof version === 'string')
    version = new SemVer(version, this.loose);

  for (var i = 0; i < this.set.length; i++) {
    if (testSet(this.set[i], version))
      return true;
  }
  return false;
};

function testSet(set, version) {
  for (var i = 0; i < set.length; i++) {
    if (!set[i].test(version))
      return false;
  }

  if (version.prerelease.length) {
    // Find the set of versions that are allowed to have prereleases
    // For example, ^1.2.3-pr.1 desugars to >=1.2.3-pr.1 <2.0.0
    // That should allow `1.2.3-pr.2` to pass.
    // However, `1.2.4-alpha.notready` should NOT be allowed,
    // even though it's within the range set by the comparators.
    for (var i = 0; i < set.length; i++) {
      debug(set[i].semver);
      if (set[i].semver === ANY)
        continue;

      if (set[i].semver.prerelease.length > 0) {
        var allowed = set[i].semver;
        if (allowed.major === version.major &&
            allowed.minor === version.minor &&
            allowed.patch === version.patch)
          return true;
      }
    }

    // Version has a -pre, but it's not one of the ones we like.
    return false;
  }

  return true;
}

exports.satisfies = satisfies;
function satisfies(version, range, loose) {
  try {
    range = new Range(range, loose);
  } catch (er) {
    return false;
  }
  return range.test(version);
}

exports.maxSatisfying = maxSatisfying;
function maxSatisfying(versions, range, loose) {
  return versions.filter(function(version) {
    return satisfies(version, range, loose);
  }).sort(function(a, b) {
    return rcompare(a, b, loose);
  })[0] || null;
}

exports.minSatisfying = minSatisfying;
function minSatisfying(versions, range, loose) {
  return versions.filter(function(version) {
    return satisfies(version, range, loose);
  }).sort(function(a, b) {
    return compare(a, b, loose);
  })[0] || null;
}

exports.validRange = validRange;
function validRange(range, loose) {
  try {
    // Return '*' instead of '' so that truthiness works.
    // This will throw if it's invalid anyway
    return new Range(range, loose).range || '*';
  } catch (er) {
    return null;
  }
}

// Determine if version is less than all the versions possible in the range
exports.ltr = ltr;
function ltr(version, range, loose) {
  return outside(version, range, '<', loose);
}

// Determine if version is greater than all the versions possible in the range.
exports.gtr = gtr;
function gtr(version, range, loose) {
  return outside(version, range, '>', loose);
}

exports.outside = outside;
function outside(version, range, hilo, loose) {
  version = new SemVer(version, loose);
  range = new Range(range, loose);

  var gtfn, ltefn, ltfn, comp, ecomp;
  switch (hilo) {
    case '>':
      gtfn = gt;
      ltefn = lte;
      ltfn = lt;
      comp = '>';
      ecomp = '>=';
      break;
    case '<':
      gtfn = lt;
      ltefn = gte;
      ltfn = gt;
      comp = '<';
      ecomp = '<=';
      break;
    default:
      throw new TypeError('Must provide a hilo val of "<" or ">"');
  }

  // If it satisifes the range it is not outside
  if (satisfies(version, range, loose)) {
    return false;
  }

  // From now on, variable terms are as if we're in "gtr" mode.
  // but note that everything is flipped for the "ltr" function.

  for (var i = 0; i < range.set.length; ++i) {
    var comparators = range.set[i];

    var high = null;
    var low = null;

    comparators.forEach(function(comparator) {
      if (comparator.semver === ANY) {
        comparator = new Comparator('>=0.0.0')
      }
      high = high || comparator;
      low = low || comparator;
      if (gtfn(comparator.semver, high.semver, loose)) {
        high = comparator;
      } else if (ltfn(comparator.semver, low.semver, loose)) {
        low = comparator;
      }
    });

    // If the edge version comparator has a operator then our version
    // isn't outside it
    if (high.operator === comp || high.operator === ecomp) {
      return false;
    }

    // If the lowest version comparator has an operator and our version
    // is less than it then it isn't higher than the range
    if ((!low.operator || low.operator === comp) &&
        ltefn(version, low.semver)) {
      return false;
    } else if (low.operator === ecomp && ltfn(version, low.semver)) {
      return false;
    }
  }
  return true;
}

exports.prerelease = prerelease;
function prerelease(version, loose) {
  var parsed = parse(version, loose);
  return (parsed && parsed.prerelease.length) ? parsed.prerelease : null;
}