modules

node_modules/semver/classes/comparator.js

@@ -0,0 +1,136 @@
+const ANY = Symbol('SemVer ANY')
+// hoisted class for cyclic dependency
+class Comparator {
+  static get ANY () {
+    return ANY
+  }
+
+  constructor (comp, options) {
+    options = parseOptions(options)
+
+    if (comp instanceof Comparator) {
+      if (comp.loose === !!options.loose) {
+        return comp
+      } else {
+        comp = comp.value
+      }
+    }
+
+    debug('comparator', comp, options)
+    this.options = options
+    this.loose = !!options.loose
+    this.parse(comp)
+
+    if (this.semver === ANY) {
+      this.value = ''
+    } else {
+      this.value = this.operator + this.semver.version
+    }
+
+    debug('comp', this)
+  }
+
+  parse (comp) {
+    const r = this.options.loose ? re[t.COMPARATORLOOSE] : re[t.COMPARATOR]
+    const m = comp.match(r)
+
+    if (!m) {
+      throw new TypeError(`Invalid comparator: ${comp}`)
+    }
+
+    this.operator = m[1] !== undefined ? 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.options.loose)
+    }
+  }
+
+  toString () {
+    return this.value
+  }
+
+  test (version) {
+    debug('Comparator.test', version, this.options.loose)
+
+    if (this.semver === ANY || version === ANY) {
+      return true
+    }
+
+    if (typeof version === 'string') {
+      try {
+        version = new SemVer(version, this.options)
+      } catch (er) {
+        return false
+      }
+    }
+
+    return cmp(version, this.operator, this.semver, this.options)
+  }
+
+  intersects (comp, options) {
+    if (!(comp instanceof Comparator)) {
+      throw new TypeError('a Comparator is required')
+    }
+
+    if (!options || typeof options !== 'object') {
+      options = {
+        loose: !!options,
+        includePrerelease: false,
+      }
+    }
+
+    if (this.operator === '') {
+      if (this.value === '') {
+        return true
+      }
+      return new Range(comp.value, options).test(this.value)
+    } else if (comp.operator === '') {
+      if (comp.value === '') {
+        return true
+      }
+      return new Range(this.value, options).test(comp.semver)
+    }
+
+    const sameDirectionIncreasing =
+      (this.operator === '>=' || this.operator === '>') &&
+      (comp.operator === '>=' || comp.operator === '>')
+    const sameDirectionDecreasing =
+      (this.operator === '<=' || this.operator === '<') &&
+      (comp.operator === '<=' || comp.operator === '<')
+    const sameSemVer = this.semver.version === comp.semver.version
+    const differentDirectionsInclusive =
+      (this.operator === '>=' || this.operator === '<=') &&
+      (comp.operator === '>=' || comp.operator === '<=')
+    const oppositeDirectionsLessThan =
+      cmp(this.semver, '<', comp.semver, options) &&
+      (this.operator === '>=' || this.operator === '>') &&
+        (comp.operator === '<=' || comp.operator === '<')
+    const oppositeDirectionsGreaterThan =
+      cmp(this.semver, '>', comp.semver, options) &&
+      (this.operator === '<=' || this.operator === '<') &&
+        (comp.operator === '>=' || comp.operator === '>')
+
+    return (
+      sameDirectionIncreasing ||
+      sameDirectionDecreasing ||
+      (sameSemVer && differentDirectionsInclusive) ||
+      oppositeDirectionsLessThan ||
+      oppositeDirectionsGreaterThan
+    )
+  }
+}
+
+module.exports = Comparator
+
+const parseOptions = require('../internal/parse-options')
+const { re, t } = require('../internal/re')
+const cmp = require('../functions/cmp')
+const debug = require('../internal/debug')
+const SemVer = require('./semver')
+const Range = require('./range')

node_modules/semver/classes/index.js

@@ -0,0 +1,5 @@
+module.exports = {
+  SemVer: require('./semver.js'),
+  Range: require('./range.js'),
+  Comparator: require('./comparator.js'),
+}

node_modules/semver/classes/range.js

@@ -0,0 +1,522 @@
+// hoisted class for cyclic dependency
+class Range {
+  constructor (range, options) {
+    options = parseOptions(options)
+
+    if (range instanceof Range) {
+      if (
+        range.loose === !!options.loose &&
+        range.includePrerelease === !!options.includePrerelease
+      ) {
+        return range
+      } else {
+        return new Range(range.raw, options)
+      }
+    }
+
+    if (range instanceof Comparator) {
+      // just put it in the set and return
+      this.raw = range.value
+      this.set = [[range]]
+      this.format()
+      return this
+    }
+
+    this.options = options
+    this.loose = !!options.loose
+    this.includePrerelease = !!options.includePrerelease
+
+    // First, split based on boolean or ||
+    this.raw = range
+    this.set = range
+      .split('||')
+      // map the range to a 2d array of comparators
+      .map(r => this.parseRange(r.trim()))
+      // throw out any comparator lists that are empty
+      // this generally means that it was not a valid range, which is allowed
+      // in loose mode, but will still throw if the WHOLE range is invalid.
+      .filter(c => c.length)
+
+    if (!this.set.length) {
+      throw new TypeError(`Invalid SemVer Range: ${range}`)
+    }
+
+    // if we have any that are not the null set, throw out null sets.
+    if (this.set.length > 1) {
+      // keep the first one, in case they're all null sets
+      const first = this.set[0]
+      this.set = this.set.filter(c => !isNullSet(c[0]))
+      if (this.set.length === 0) {
+        this.set = [first]
+      } else if (this.set.length > 1) {
+        // if we have any that are *, then the range is just *
+        for (const c of this.set) {
+          if (c.length === 1 && isAny(c[0])) {
+            this.set = [c]
+            break
+          }
+        }
+      }
+    }
+
+    this.format()
+  }
+
+  format () {
+    this.range = this.set
+      .map((comps) => {
+        return comps.join(' ').trim()
+      })
+      .join('||')
+      .trim()
+    return this.range
+  }
+
+  toString () {
+    return this.range
+  }
+
+  parseRange (range) {
+    range = range.trim()
+
+    // memoize range parsing for performance.
+    // this is a very hot path, and fully deterministic.
+    const memoOpts = Object.keys(this.options).join(',')
+    const memoKey = `parseRange:${memoOpts}:${range}`
+    const cached = cache.get(memoKey)
+    if (cached) {
+      return cached
+    }
+
+    const loose = this.options.loose
+    // `1.2.3 - 1.2.4` => `>=1.2.3 <=1.2.4`
+    const hr = loose ? re[t.HYPHENRANGELOOSE] : re[t.HYPHENRANGE]
+    range = range.replace(hr, hyphenReplace(this.options.includePrerelease))
+    debug('hyphen replace', range)
+    // `> 1.2.3 < 1.2.5` => `>1.2.3 <1.2.5`
+    range = range.replace(re[t.COMPARATORTRIM], comparatorTrimReplace)
+    debug('comparator trim', range)
+
+    // `~ 1.2.3` => `~1.2.3`
+    range = range.replace(re[t.TILDETRIM], tildeTrimReplace)
+
+    // `^ 1.2.3` => `^1.2.3`
+    range = range.replace(re[t.CARETTRIM], caretTrimReplace)
+
+    // normalize spaces
+    range = range.split(/\s+/).join(' ')
+
+    // At this point, the range is completely trimmed and
+    // ready to be split into comparators.
+
+    let rangeList = range
+      .split(' ')
+      .map(comp => parseComparator(comp, this.options))
+      .join(' ')
+      .split(/\s+/)
+      // >=0.0.0 is equivalent to *
+      .map(comp => replaceGTE0(comp, this.options))
+
+    if (loose) {
+      // in loose mode, throw out any that are not valid comparators
+      rangeList = rangeList.filter(comp => {
+        debug('loose invalid filter', comp, this.options)
+        return !!comp.match(re[t.COMPARATORLOOSE])
+      })
+    }
+    debug('range list', rangeList)
+
+    // if any comparators are the null set, then replace with JUST null set
+    // if more than one comparator, remove any * comparators
+    // also, don't include the same comparator more than once
+    const rangeMap = new Map()
+    const comparators = rangeList.map(comp => new Comparator(comp, this.options))
+    for (const comp of comparators) {
+      if (isNullSet(comp)) {
+        return [comp]
+      }
+      rangeMap.set(comp.value, comp)
+    }
+    if (rangeMap.size > 1 && rangeMap.has('')) {
+      rangeMap.delete('')
+    }
+
+    const result = [...rangeMap.values()]
+    cache.set(memoKey, result)
+    return result
+  }
+
+  intersects (range, options) {
+    if (!(range instanceof Range)) {
+      throw new TypeError('a Range is required')
+    }
+
+    return this.set.some((thisComparators) => {
+      return (
+        isSatisfiable(thisComparators, options) &&
+        range.set.some((rangeComparators) => {
+          return (
+            isSatisfiable(rangeComparators, options) &&
+            thisComparators.every((thisComparator) => {
+              return rangeComparators.every((rangeComparator) => {
+                return thisComparator.intersects(rangeComparator, options)
+              })
+            })
+          )
+        })
+      )
+    })
+  }
+
+  // if ANY of the sets match ALL of its comparators, then pass
+  test (version) {
+    if (!version) {
+      return false
+    }
+
+    if (typeof version === 'string') {
+      try {
+        version = new SemVer(version, this.options)
+      } catch (er) {
+        return false
+      }
+    }
+
+    for (let i = 0; i < this.set.length; i++) {
+      if (testSet(this.set[i], version, this.options)) {
+        return true
+      }
+    }
+    return false
+  }
+}
+module.exports = Range
+
+const LRU = require('lru-cache')
+const cache = new LRU({ max: 1000 })
+
+const parseOptions = require('../internal/parse-options')
+const Comparator = require('./comparator')
+const debug = require('../internal/debug')
+const SemVer = require('./semver')
+const {
+  re,
+  t,
+  comparatorTrimReplace,
+  tildeTrimReplace,
+  caretTrimReplace,
+} = require('../internal/re')
+
+const isNullSet = c => c.value === '<0.0.0-0'
+const isAny = c => c.value === ''
+
+// take a set of comparators and determine whether there
+// exists a version which can satisfy it
+const isSatisfiable = (comparators, options) => {
+  let result = true
+  const remainingComparators = comparators.slice()
+  let testComparator = remainingComparators.pop()
+
+  while (result && remainingComparators.length) {
+    result = remainingComparators.every((otherComparator) => {
+      return testComparator.intersects(otherComparator, options)
+    })
+
+    testComparator = remainingComparators.pop()
+  }
+
+  return result
+}
+
+// comprised of xranges, tildes, stars, and gtlt's at this point.
+// already replaced the hyphen ranges
+// turn into a set of JUST comparators.
+const parseComparator = (comp, options) => {
+  debug('comp', comp, options)
+  comp = replaceCarets(comp, options)
+  debug('caret', comp)
+  comp = replaceTildes(comp, options)
+  debug('tildes', comp)
+  comp = replaceXRanges(comp, options)
+  debug('xrange', comp)
+  comp = replaceStars(comp, options)
+  debug('stars', comp)
+  return comp
+}
+
+const isX = id => !id || id.toLowerCase() === 'x' || id === '*'
+
+// ~, ~> --> * (any, kinda silly)
+// ~2, ~2.x, ~2.x.x, ~>2, ~>2.x ~>2.x.x --> >=2.0.0 <3.0.0-0
+// ~2.0, ~2.0.x, ~>2.0, ~>2.0.x --> >=2.0.0 <2.1.0-0
+// ~1.2, ~1.2.x, ~>1.2, ~>1.2.x --> >=1.2.0 <1.3.0-0
+// ~1.2.3, ~>1.2.3 --> >=1.2.3 <1.3.0-0
+// ~1.2.0, ~>1.2.0 --> >=1.2.0 <1.3.0-0
+// ~0.0.1 --> >=0.0.1 <0.1.0-0
+const replaceTildes = (comp, options) =>
+  comp.trim().split(/\s+/).map((c) => {
+    return replaceTilde(c, options)
+  }).join(' ')
+
+const replaceTilde = (comp, options) => {
+  const r = options.loose ? re[t.TILDELOOSE] : re[t.TILDE]
+  return comp.replace(r, (_, M, m, p, pr) => {
+    debug('tilde', comp, _, M, m, p, pr)
+    let ret
+
+    if (isX(M)) {
+      ret = ''
+    } else if (isX(m)) {
+      ret = `>=${M}.0.0 <${+M + 1}.0.0-0`
+    } else if (isX(p)) {
+      // ~1.2 == >=1.2.0 <1.3.0-0
+      ret = `>=${M}.${m}.0 <${M}.${+m + 1}.0-0`
+    } else if (pr) {
+      debug('replaceTilde pr', pr)
+      ret = `>=${M}.${m}.${p}-${pr
+      } <${M}.${+m + 1}.0-0`
+    } else {
+      // ~1.2.3 == >=1.2.3 <1.3.0-0
+      ret = `>=${M}.${m}.${p
+      } <${M}.${+m + 1}.0-0`
+    }
+
+    debug('tilde return', ret)
+    return ret
+  })
+}
+
+// ^ --> * (any, kinda silly)
+// ^2, ^2.x, ^2.x.x --> >=2.0.0 <3.0.0-0
+// ^2.0, ^2.0.x --> >=2.0.0 <3.0.0-0
+// ^1.2, ^1.2.x --> >=1.2.0 <2.0.0-0
+// ^1.2.3 --> >=1.2.3 <2.0.0-0
+// ^1.2.0 --> >=1.2.0 <2.0.0-0
+// ^0.0.1 --> >=0.0.1 <0.0.2-0
+// ^0.1.0 --> >=0.1.0 <0.2.0-0
+const replaceCarets = (comp, options) =>
+  comp.trim().split(/\s+/).map((c) => {
+    return replaceCaret(c, options)
+  }).join(' ')
+
+const replaceCaret = (comp, options) => {
+  debug('caret', comp, options)
+  const r = options.loose ? re[t.CARETLOOSE] : re[t.CARET]
+  const z = options.includePrerelease ? '-0' : ''
+  return comp.replace(r, (_, M, m, p, pr) => {
+    debug('caret', comp, _, M, m, p, pr)
+    let ret
+
+    if (isX(M)) {
+      ret = ''
+    } else if (isX(m)) {
+      ret = `>=${M}.0.0${z} <${+M + 1}.0.0-0`
+    } else if (isX(p)) {
+      if (M === '0') {
+        ret = `>=${M}.${m}.0${z} <${M}.${+m + 1}.0-0`
+      } else {
+        ret = `>=${M}.${m}.0${z} <${+M + 1}.0.0-0`
+      }
+    } else if (pr) {
+      debug('replaceCaret pr', pr)
+      if (M === '0') {
+        if (m === '0') {
+          ret = `>=${M}.${m}.${p}-${pr
+          } <${M}.${m}.${+p + 1}-0`
+        } else {
+          ret = `>=${M}.${m}.${p}-${pr
+          } <${M}.${+m + 1}.0-0`
+        }
+      } else {
+        ret = `>=${M}.${m}.${p}-${pr
+        } <${+M + 1}.0.0-0`
+      }
+    } else {
+      debug('no pr')
+      if (M === '0') {
+        if (m === '0') {
+          ret = `>=${M}.${m}.${p
+          }${z} <${M}.${m}.${+p + 1}-0`
+        } else {
+          ret = `>=${M}.${m}.${p
+          }${z} <${M}.${+m + 1}.0-0`
+        }
+      } else {
+        ret = `>=${M}.${m}.${p
+        } <${+M + 1}.0.0-0`
+      }
+    }
+
+    debug('caret return', ret)
+    return ret
+  })
+}
+
+const replaceXRanges = (comp, options) => {
+  debug('replaceXRanges', comp, options)
+  return comp.split(/\s+/).map((c) => {
+    return replaceXRange(c, options)
+  }).join(' ')
+}
+
+const replaceXRange = (comp, options) => {
+  comp = comp.trim()
+  const r = options.loose ? re[t.XRANGELOOSE] : re[t.XRANGE]
+  return comp.replace(r, (ret, gtlt, M, m, p, pr) => {
+    debug('xRange', comp, ret, gtlt, M, m, p, pr)
+    const xM = isX(M)
+    const xm = xM || isX(m)
+    const xp = xm || isX(p)
+    const anyX = xp
+
+    if (gtlt === '=' && anyX) {
+      gtlt = ''
+    }
+
+    // if we're including prereleases in the match, then we need
+    // to fix this to -0, the lowest possible prerelease value
+    pr = options.includePrerelease ? '-0' : ''
+
+    if (xM) {
+      if (gtlt === '>' || gtlt === '<') {
+        // nothing is allowed
+        ret = '<0.0.0-0'
+      } else {
+        // nothing is forbidden
+        ret = '*'
+      }
+    } else if (gtlt && anyX) {
+      // we know patch is an x, because we have any x at all.
+      // replace X with 0
+      if (xm) {
+        m = 0
+      }
+      p = 0
+
+      if (gtlt === '>') {
+        // >1 => >=2.0.0
+        // >1.2 => >=1.3.0
+        gtlt = '>='
+        if (xm) {
+          M = +M + 1
+          m = 0
+          p = 0
+        } else {
+          m = +m + 1
+          p = 0
+        }
+      } else if (gtlt === '<=') {
+        // <=0.7.x is actually <0.8.0, since any 0.7.x should
+        // pass.  Similarly, <=7.x is actually <8.0.0, etc.
+        gtlt = '<'
+        if (xm) {
+          M = +M + 1
+        } else {
+          m = +m + 1
+        }
+      }
+
+      if (gtlt === '<') {
+        pr = '-0'
+      }
+
+      ret = `${gtlt + M}.${m}.${p}${pr}`
+    } else if (xm) {
+      ret = `>=${M}.0.0${pr} <${+M + 1}.0.0-0`
+    } else if (xp) {
+      ret = `>=${M}.${m}.0${pr
+      } <${M}.${+m + 1}.0-0`
+    }
+
+    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.
+const replaceStars = (comp, options) => {
+  debug('replaceStars', comp, options)
+  // Looseness is ignored here.  star is always as loose as it gets!
+  return comp.trim().replace(re[t.STAR], '')
+}
+
+const replaceGTE0 = (comp, options) => {
+  debug('replaceGTE0', comp, options)
+  return comp.trim()
+    .replace(re[options.includePrerelease ? t.GTE0PRE : t.GTE0], '')
+}
+
+// This function is passed to string.replace(re[t.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 <3.5.0-0 Any 3.4.x will do
+// 1.2 - 3.4 => >=1.2.0 <3.5.0-0
+const hyphenReplace = incPr => ($0,
+  from, fM, fm, fp, fpr, fb,
+  to, tM, tm, tp, tpr, tb) => {
+  if (isX(fM)) {
+    from = ''
+  } else if (isX(fm)) {
+    from = `>=${fM}.0.0${incPr ? '-0' : ''}`
+  } else if (isX(fp)) {
+    from = `>=${fM}.${fm}.0${incPr ? '-0' : ''}`
+  } else if (fpr) {
+    from = `>=${from}`
+  } else {
+    from = `>=${from}${incPr ? '-0' : ''}`
+  }
+
+  if (isX(tM)) {
+    to = ''
+  } else if (isX(tm)) {
+    to = `<${+tM + 1}.0.0-0`
+  } else if (isX(tp)) {
+    to = `<${tM}.${+tm + 1}.0-0`
+  } else if (tpr) {
+    to = `<=${tM}.${tm}.${tp}-${tpr}`
+  } else if (incPr) {
+    to = `<${tM}.${tm}.${+tp + 1}-0`
+  } else {
+    to = `<=${to}`
+  }
+
+  return (`${from} ${to}`).trim()
+}
+
+const testSet = (set, version, options) => {
+  for (let i = 0; i < set.length; i++) {
+    if (!set[i].test(version)) {
+      return false
+    }
+  }
+
+  if (version.prerelease.length && !options.includePrerelease) {
+    // 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 (let i = 0; i < set.length; i++) {
+      debug(set[i].semver)
+      if (set[i].semver === Comparator.ANY) {
+        continue
+      }
+
+      if (set[i].semver.prerelease.length > 0) {
+        const 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
+}

node_modules/semver/classes/semver.js

@@ -0,0 +1,287 @@
+const debug = require('../internal/debug')
+const { MAX_LENGTH, MAX_SAFE_INTEGER } = require('../internal/constants')
+const { re, t } = require('../internal/re')
+
+const parseOptions = require('../internal/parse-options')
+const { compareIdentifiers } = require('../internal/identifiers')
+class SemVer {
+  constructor (version, options) {
+    options = parseOptions(options)
+
+    if (version instanceof SemVer) {
+      if (version.loose === !!options.loose &&
+          version.includePrerelease === !!options.includePrerelease) {
+        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`
+      )
+    }
+
+    debug('SemVer', version, options)
+    this.options = options
+    this.loose = !!options.loose
+    // this isn't actually relevant for versions, but keep it so that we
+    // don't run into trouble passing this.options around.
+    this.includePrerelease = !!options.includePrerelease
+
+    const m = version.trim().match(options.loose ? re[t.LOOSE] : re[t.FULL])
+
+    if (!m) {
+      throw new TypeError(`Invalid Version: ${version}`)
+    }
+
+    this.raw = version
+
+    // these are actually numbers
+    this.major = +m[1]
+    this.minor = +m[2]
+    this.patch = +m[3]
+
+    if (this.major > MAX_SAFE_INTEGER || this.major < 0) {
+      throw new TypeError('Invalid major version')
+    }
+
+    if (this.minor > MAX_SAFE_INTEGER || this.minor < 0) {
+      throw new TypeError('Invalid minor version')
+    }
+
+    if (this.patch > MAX_SAFE_INTEGER || this.patch < 0) {
+      throw new TypeError('Invalid patch version')
+    }
+
+    // numberify any prerelease numeric ids
+    if (!m[4]) {
+      this.prerelease = []
+    } else {
+      this.prerelease = m[4].split('.').map((id) => {
+        if (/^[0-9]+$/.test(id)) {
+          const num = +id
+          if (num >= 0 && num < MAX_SAFE_INTEGER) {
+            return num
+          }
+        }
+        return id
+      })
+    }
+
+    this.build = m[5] ? m[5].split('.') : []
+    this.format()
+  }
+
+  format () {
+    this.version = `${this.major}.${this.minor}.${this.patch}`
+    if (this.prerelease.length) {
+      this.version += `-${this.prerelease.join('.')}`
+    }
+    return this.version
+  }
+
+  toString () {
+    return this.version
+  }
+
+  compare (other) {
+    debug('SemVer.compare', this.version, this.options, other)
+    if (!(other instanceof SemVer)) {
+      if (typeof other === 'string' && other === this.version) {
+        return 0
+      }
+      other = new SemVer(other, this.options)
+    }
+
+    if (other.version === this.version) {
+      return 0
+    }
+
+    return this.compareMain(other) || this.comparePre(other)
+  }
+
+  compareMain (other) {
+    if (!(other instanceof SemVer)) {
+      other = new SemVer(other, this.options)
+    }
+
+    return (
+      compareIdentifiers(this.major, other.major) ||
+      compareIdentifiers(this.minor, other.minor) ||
+      compareIdentifiers(this.patch, other.patch)
+    )
+  }
+
+  comparePre (other) {
+    if (!(other instanceof SemVer)) {
+      other = new SemVer(other, this.options)
+    }
+
+    // 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
+    }
+
+    let i = 0
+    do {
+      const a = this.prerelease[i]
+      const 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)
+  }
+
+  compareBuild (other) {
+    if (!(other instanceof SemVer)) {
+      other = new SemVer(other, this.options)
+    }
+
+    let i = 0
+    do {
+      const a = this.build[i]
+      const b = other.build[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.
+  inc (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 {
+          let 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 (compareIdentifiers(this.prerelease[0], identifier) === 0) {
+            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
+  }
+}
+
+module.exports = SemVer