Index: trip-planner-front/node_modules/yargs-parser/index.js
===================================================================
--- trip-planner-front/node_modules/yargs-parser/index.js	(revision e29cc2ea91f8c99a4329f6d20188305dfd752279)
+++ trip-planner-front/node_modules/yargs-parser/index.js	(revision e29cc2ea91f8c99a4329f6d20188305dfd752279)
@@ -0,0 +1,916 @@
+var camelCase = require('camelcase')
+var decamelize = require('decamelize')
+var path = require('path')
+var tokenizeArgString = require('./lib/tokenize-arg-string')
+var util = require('util')
+
+function parse (args, opts) {
+  if (!opts) opts = {}
+  // allow a string argument to be passed in rather
+  // than an argv array.
+  args = tokenizeArgString(args)
+
+  // aliases might have transitive relationships, normalize this.
+  var aliases = combineAliases(opts.alias || {})
+  var configuration = Object.assign({
+    'short-option-groups': true,
+    'camel-case-expansion': true,
+    'dot-notation': true,
+    'parse-numbers': true,
+    'boolean-negation': true,
+    'negation-prefix': 'no-',
+    'duplicate-arguments-array': true,
+    'flatten-duplicate-arrays': true,
+    'populate--': false,
+    'combine-arrays': false,
+    'set-placeholder-key': false,
+    'halt-at-non-option': false,
+    'strip-aliased': false,
+    'strip-dashed': false
+  }, opts.configuration)
+  var defaults = opts.default || {}
+  var configObjects = opts.configObjects || []
+  var envPrefix = opts.envPrefix
+  var notFlagsOption = configuration['populate--']
+  var notFlagsArgv = notFlagsOption ? '--' : '_'
+  var newAliases = {}
+  // allow a i18n handler to be passed in, default to a fake one (util.format).
+  var __ = opts.__ || util.format
+  var error = null
+  var flags = {
+    aliases: {},
+    arrays: {},
+    bools: {},
+    strings: {},
+    numbers: {},
+    counts: {},
+    normalize: {},
+    configs: {},
+    defaulted: {},
+    nargs: {},
+    coercions: {},
+    keys: []
+  }
+  var negative = /^-[0-9]+(\.[0-9]+)?/
+  var negatedBoolean = new RegExp('^--' + configuration['negation-prefix'] + '(.+)')
+
+  ;[].concat(opts.array).filter(Boolean).forEach(function (opt) {
+    var key = opt.key || opt
+
+    // assign to flags[bools|strings|numbers]
+    const assignment = Object.keys(opt).map(function (key) {
+      return ({
+        boolean: 'bools',
+        string: 'strings',
+        number: 'numbers'
+      })[key]
+    }).filter(Boolean).pop()
+
+    // assign key to be coerced
+    if (assignment) {
+      flags[assignment][key] = true
+    }
+
+    flags.arrays[key] = true
+    flags.keys.push(key)
+  })
+
+  ;[].concat(opts.boolean).filter(Boolean).forEach(function (key) {
+    flags.bools[key] = true
+    flags.keys.push(key)
+  })
+
+  ;[].concat(opts.string).filter(Boolean).forEach(function (key) {
+    flags.strings[key] = true
+    flags.keys.push(key)
+  })
+
+  ;[].concat(opts.number).filter(Boolean).forEach(function (key) {
+    flags.numbers[key] = true
+    flags.keys.push(key)
+  })
+
+  ;[].concat(opts.count).filter(Boolean).forEach(function (key) {
+    flags.counts[key] = true
+    flags.keys.push(key)
+  })
+
+  ;[].concat(opts.normalize).filter(Boolean).forEach(function (key) {
+    flags.normalize[key] = true
+    flags.keys.push(key)
+  })
+
+  Object.keys(opts.narg || {}).forEach(function (k) {
+    flags.nargs[k] = opts.narg[k]
+    flags.keys.push(k)
+  })
+
+  Object.keys(opts.coerce || {}).forEach(function (k) {
+    flags.coercions[k] = opts.coerce[k]
+    flags.keys.push(k)
+  })
+
+  if (Array.isArray(opts.config) || typeof opts.config === 'string') {
+    ;[].concat(opts.config).filter(Boolean).forEach(function (key) {
+      flags.configs[key] = true
+    })
+  } else {
+    Object.keys(opts.config || {}).forEach(function (k) {
+      flags.configs[k] = opts.config[k]
+    })
+  }
+
+  // create a lookup table that takes into account all
+  // combinations of aliases: {f: ['foo'], foo: ['f']}
+  extendAliases(opts.key, aliases, opts.default, flags.arrays)
+
+  // apply default values to all aliases.
+  Object.keys(defaults).forEach(function (key) {
+    (flags.aliases[key] || []).forEach(function (alias) {
+      defaults[alias] = defaults[key]
+    })
+  })
+
+  var argv = { _: [] }
+
+  Object.keys(flags.bools).forEach(function (key) {
+    if (Object.prototype.hasOwnProperty.call(defaults, key)) {
+      setArg(key, defaults[key])
+      setDefaulted(key)
+    }
+  })
+
+  var notFlags = []
+
+  for (var i = 0; i < args.length; i++) {
+    var arg = args[i]
+    var broken
+    var key
+    var letters
+    var m
+    var next
+    var value
+
+    // -- separated by =
+    if (arg.match(/^--.+=/) || (
+      !configuration['short-option-groups'] && arg.match(/^-.+=/)
+    )) {
+      // Using [\s\S] instead of . because js doesn't support the
+      // 'dotall' regex modifier. See:
+      // http://stackoverflow.com/a/1068308/13216
+      m = arg.match(/^--?([^=]+)=([\s\S]*)$/)
+
+      // nargs format = '--f=monkey washing cat'
+      if (checkAllAliases(m[1], flags.nargs)) {
+        args.splice(i + 1, 0, m[2])
+        i = eatNargs(i, m[1], args)
+      // arrays format = '--f=a b c'
+      } else if (checkAllAliases(m[1], flags.arrays) && args.length > i + 1) {
+        args.splice(i + 1, 0, m[2])
+        i = eatArray(i, m[1], args)
+      } else {
+        setArg(m[1], m[2])
+      }
+    } else if (arg.match(negatedBoolean) && configuration['boolean-negation']) {
+      key = arg.match(negatedBoolean)[1]
+      setArg(key, false)
+
+    // -- seperated by space.
+    } else if (arg.match(/^--.+/) || (
+      !configuration['short-option-groups'] && arg.match(/^-[^-]+/)
+    )) {
+      key = arg.match(/^--?(.+)/)[1]
+
+      // nargs format = '--foo a b c'
+      if (checkAllAliases(key, flags.nargs)) {
+        i = eatNargs(i, key, args)
+      // array format = '--foo a b c'
+      } else if (checkAllAliases(key, flags.arrays) && args.length > i + 1) {
+        i = eatArray(i, key, args)
+      } else {
+        next = flags.nargs[key] === 0 ? undefined : args[i + 1]
+
+        if (next !== undefined && (!next.match(/^-/) ||
+          next.match(negative)) &&
+          !checkAllAliases(key, flags.bools) &&
+          !checkAllAliases(key, flags.counts)) {
+          setArg(key, next)
+          i++
+        } else if (/^(true|false)$/.test(next)) {
+          setArg(key, next)
+          i++
+        } else {
+          setArg(key, defaultValue(key))
+        }
+      }
+
+    // dot-notation flag seperated by '='.
+    } else if (arg.match(/^-.\..+=/)) {
+      m = arg.match(/^-([^=]+)=([\s\S]*)$/)
+      setArg(m[1], m[2])
+
+    // dot-notation flag seperated by space.
+    } else if (arg.match(/^-.\..+/)) {
+      next = args[i + 1]
+      key = arg.match(/^-(.\..+)/)[1]
+
+      if (next !== undefined && !next.match(/^-/) &&
+        !checkAllAliases(key, flags.bools) &&
+        !checkAllAliases(key, flags.counts)) {
+        setArg(key, next)
+        i++
+      } else {
+        setArg(key, defaultValue(key))
+      }
+    } else if (arg.match(/^-[^-]+/) && !arg.match(negative)) {
+      letters = arg.slice(1, -1).split('')
+      broken = false
+
+      for (var j = 0; j < letters.length; j++) {
+        next = arg.slice(j + 2)
+
+        if (letters[j + 1] && letters[j + 1] === '=') {
+          value = arg.slice(j + 3)
+          key = letters[j]
+
+          // nargs format = '-f=monkey washing cat'
+          if (checkAllAliases(key, flags.nargs)) {
+            args.splice(i + 1, 0, value)
+            i = eatNargs(i, key, args)
+          // array format = '-f=a b c'
+          } else if (checkAllAliases(key, flags.arrays) && args.length > i + 1) {
+            args.splice(i + 1, 0, value)
+            i = eatArray(i, key, args)
+          } else {
+            setArg(key, value)
+          }
+
+          broken = true
+          break
+        }
+
+        if (next === '-') {
+          setArg(letters[j], next)
+          continue
+        }
+
+        // current letter is an alphabetic character and next value is a number
+        if (/[A-Za-z]/.test(letters[j]) &&
+          /^-?\d+(\.\d*)?(e-?\d+)?$/.test(next)) {
+          setArg(letters[j], next)
+          broken = true
+          break
+        }
+
+        if (letters[j + 1] && letters[j + 1].match(/\W/)) {
+          setArg(letters[j], next)
+          broken = true
+          break
+        } else {
+          setArg(letters[j], defaultValue(letters[j]))
+        }
+      }
+
+      key = arg.slice(-1)[0]
+
+      if (!broken && key !== '-') {
+        // nargs format = '-f a b c'
+        if (checkAllAliases(key, flags.nargs)) {
+          i = eatNargs(i, key, args)
+        // array format = '-f a b c'
+        } else if (checkAllAliases(key, flags.arrays) && args.length > i + 1) {
+          i = eatArray(i, key, args)
+        } else {
+          next = args[i + 1]
+
+          if (next !== undefined && (!/^(-|--)[^-]/.test(next) ||
+            next.match(negative)) &&
+            !checkAllAliases(key, flags.bools) &&
+            !checkAllAliases(key, flags.counts)) {
+            setArg(key, next)
+            i++
+          } else if (/^(true|false)$/.test(next)) {
+            setArg(key, next)
+            i++
+          } else {
+            setArg(key, defaultValue(key))
+          }
+        }
+      }
+    } else if (arg === '--') {
+      notFlags = args.slice(i + 1)
+      break
+    } else if (configuration['halt-at-non-option']) {
+      notFlags = args.slice(i)
+      break
+    } else {
+      argv._.push(maybeCoerceNumber('_', arg))
+    }
+  }
+
+  // order of precedence:
+  // 1. command line arg
+  // 2. value from env var
+  // 3. value from config file
+  // 4. value from config objects
+  // 5. configured default value
+  applyEnvVars(argv, true) // special case: check env vars that point to config file
+  applyEnvVars(argv, false)
+  setConfig(argv)
+  setConfigObjects()
+  applyDefaultsAndAliases(argv, flags.aliases, defaults)
+  applyCoercions(argv)
+  if (configuration['set-placeholder-key']) setPlaceholderKeys(argv)
+
+  // for any counts either not in args or without an explicit default, set to 0
+  Object.keys(flags.counts).forEach(function (key) {
+    if (!hasKey(argv, key.split('.'))) setArg(key, 0)
+  })
+
+  // '--' defaults to undefined.
+  if (notFlagsOption && notFlags.length) argv[notFlagsArgv] = []
+  notFlags.forEach(function (key) {
+    argv[notFlagsArgv].push(key)
+  })
+
+  if (configuration['camel-case-expansion'] && configuration['strip-dashed']) {
+    Object.keys(argv).filter(key => key !== '--' && key.includes('-')).forEach(key => {
+      delete argv[key]
+    })
+  }
+
+  if (configuration['strip-aliased']) {
+    // XXX Switch to [].concat(...Object.values(aliases)) once node.js 6 is dropped
+    ;[].concat(...Object.keys(aliases).map(k => aliases[k])).forEach(alias => {
+      if (configuration['camel-case-expansion']) {
+        delete argv[alias.split('.').map(prop => camelCase(prop)).join('.')]
+      }
+
+      delete argv[alias]
+    })
+  }
+
+  // how many arguments should we consume, based
+  // on the nargs option?
+  function eatNargs (i, key, args) {
+    var ii
+    const toEat = checkAllAliases(key, flags.nargs)
+
+    // nargs will not consume flag arguments, e.g., -abc, --foo,
+    // and terminates when one is observed.
+    var available = 0
+    for (ii = i + 1; ii < args.length; ii++) {
+      if (!args[ii].match(/^-[^0-9]/)) available++
+      else break
+    }
+
+    if (available < toEat) error = Error(__('Not enough arguments following: %s', key))
+
+    const consumed = Math.min(available, toEat)
+    for (ii = i + 1; ii < (consumed + i + 1); ii++) {
+      setArg(key, args[ii])
+    }
+
+    return (i + consumed)
+  }
+
+  // if an option is an array, eat all non-hyphenated arguments
+  // following it... YUM!
+  // e.g., --foo apple banana cat becomes ["apple", "banana", "cat"]
+  function eatArray (i, key, args) {
+    var start = i + 1
+    var argsToSet = []
+    var multipleArrayFlag = i > 0
+    for (var ii = i + 1; ii < args.length; ii++) {
+      if (/^-/.test(args[ii]) && !negative.test(args[ii])) {
+        if (ii === start) {
+          setArg(key, defaultForType('array'))
+        }
+        multipleArrayFlag = true
+        break
+      }
+      i = ii
+      argsToSet.push(args[ii])
+    }
+    if (multipleArrayFlag) {
+      setArg(key, argsToSet.map(function (arg) {
+        return processValue(key, arg)
+      }))
+    } else {
+      argsToSet.forEach(function (arg) {
+        setArg(key, arg)
+      })
+    }
+
+    return i
+  }
+
+  function setArg (key, val) {
+    unsetDefaulted(key)
+
+    if (/-/.test(key) && configuration['camel-case-expansion']) {
+      var alias = key.split('.').map(function (prop) {
+        return camelCase(prop)
+      }).join('.')
+      addNewAlias(key, alias)
+    }
+
+    var value = processValue(key, val)
+
+    var splitKey = key.split('.')
+    setKey(argv, splitKey, value)
+
+    // handle populating aliases of the full key
+    if (flags.aliases[key] && flags.aliases[key].forEach) {
+      flags.aliases[key].forEach(function (x) {
+        x = x.split('.')
+        setKey(argv, x, value)
+      })
+    }
+
+    // handle populating aliases of the first element of the dot-notation key
+    if (splitKey.length > 1 && configuration['dot-notation']) {
+      ;(flags.aliases[splitKey[0]] || []).forEach(function (x) {
+        x = x.split('.')
+
+        // expand alias with nested objects in key
+        var a = [].concat(splitKey)
+        a.shift() // nuke the old key.
+        x = x.concat(a)
+
+        setKey(argv, x, value)
+      })
+    }
+
+    // Set normalize getter and setter when key is in 'normalize' but isn't an array
+    if (checkAllAliases(key, flags.normalize) && !checkAllAliases(key, flags.arrays)) {
+      var keys = [key].concat(flags.aliases[key] || [])
+      keys.forEach(function (key) {
+        argv.__defineSetter__(key, function (v) {
+          val = path.normalize(v)
+        })
+
+        argv.__defineGetter__(key, function () {
+          return typeof val === 'string' ? path.normalize(val) : val
+        })
+      })
+    }
+  }
+
+  function addNewAlias (key, alias) {
+    if (!(flags.aliases[key] && flags.aliases[key].length)) {
+      flags.aliases[key] = [alias]
+      newAliases[alias] = true
+    }
+    if (!(flags.aliases[alias] && flags.aliases[alias].length)) {
+      addNewAlias(alias, key)
+    }
+  }
+
+  function processValue (key, val) {
+    // strings may be quoted, clean this up as we assign values.
+    if (typeof val === 'string' &&
+      (val[0] === "'" || val[0] === '"') &&
+      val[val.length - 1] === val[0]
+    ) {
+      val = val.substring(1, val.length - 1)
+    }
+
+    // handle parsing boolean arguments --foo=true --bar false.
+    if (checkAllAliases(key, flags.bools) || checkAllAliases(key, flags.counts)) {
+      if (typeof val === 'string') val = val === 'true'
+    }
+
+    var value = maybeCoerceNumber(key, val)
+
+    // increment a count given as arg (either no value or value parsed as boolean)
+    if (checkAllAliases(key, flags.counts) && (isUndefined(value) || typeof value === 'boolean')) {
+      value = increment
+    }
+
+    // Set normalized value when key is in 'normalize' and in 'arrays'
+    if (checkAllAliases(key, flags.normalize) && checkAllAliases(key, flags.arrays)) {
+      if (Array.isArray(val)) value = val.map(path.normalize)
+      else value = path.normalize(val)
+    }
+    return value
+  }
+
+  function maybeCoerceNumber (key, value) {
+    if (!checkAllAliases(key, flags.strings) && !checkAllAliases(key, flags.coercions)) {
+      const shouldCoerceNumber = isNumber(value) && configuration['parse-numbers'] && (
+        Number.isSafeInteger(Math.floor(value))
+      )
+      if (shouldCoerceNumber || (!isUndefined(value) && checkAllAliases(key, flags.numbers))) value = Number(value)
+    }
+    return value
+  }
+
+  // set args from config.json file, this should be
+  // applied last so that defaults can be applied.
+  function setConfig (argv) {
+    var configLookup = {}
+
+    // expand defaults/aliases, in-case any happen to reference
+    // the config.json file.
+    applyDefaultsAndAliases(configLookup, flags.aliases, defaults)
+
+    Object.keys(flags.configs).forEach(function (configKey) {
+      var configPath = argv[configKey] || configLookup[configKey]
+      if (configPath) {
+        try {
+          var config = null
+          var resolvedConfigPath = path.resolve(process.cwd(), configPath)
+
+          if (typeof flags.configs[configKey] === 'function') {
+            try {
+              config = flags.configs[configKey](resolvedConfigPath)
+            } catch (e) {
+              config = e
+            }
+            if (config instanceof Error) {
+              error = config
+              return
+            }
+          } else {
+            config = require(resolvedConfigPath)
+          }
+
+          setConfigObject(config)
+        } catch (ex) {
+          if (argv[configKey]) error = Error(__('Invalid JSON config file: %s', configPath))
+        }
+      }
+    })
+  }
+
+  // set args from config object.
+  // it recursively checks nested objects.
+  function setConfigObject (config, prev) {
+    Object.keys(config).forEach(function (key) {
+      var value = config[key]
+      var fullKey = prev ? prev + '.' + key : key
+
+      // if the value is an inner object and we have dot-notation
+      // enabled, treat inner objects in config the same as
+      // heavily nested dot notations (foo.bar.apple).
+      if (typeof value === 'object' && value !== null && !Array.isArray(value) && configuration['dot-notation']) {
+        // if the value is an object but not an array, check nested object
+        setConfigObject(value, fullKey)
+      } else {
+        // setting arguments via CLI takes precedence over
+        // values within the config file.
+        if (!hasKey(argv, fullKey.split('.')) || (flags.defaulted[fullKey]) || (flags.arrays[fullKey] && configuration['combine-arrays'])) {
+          setArg(fullKey, value)
+        }
+      }
+    })
+  }
+
+  // set all config objects passed in opts
+  function setConfigObjects () {
+    if (typeof configObjects === 'undefined') return
+    configObjects.forEach(function (configObject) {
+      setConfigObject(configObject)
+    })
+  }
+
+  function applyEnvVars (argv, configOnly) {
+    if (typeof envPrefix === 'undefined') return
+
+    var prefix = typeof envPrefix === 'string' ? envPrefix : ''
+    Object.keys(process.env).forEach(function (envVar) {
+      if (prefix === '' || envVar.lastIndexOf(prefix, 0) === 0) {
+        // get array of nested keys and convert them to camel case
+        var keys = envVar.split('__').map(function (key, i) {
+          if (i === 0) {
+            key = key.substring(prefix.length)
+          }
+          return camelCase(key)
+        })
+
+        if (((configOnly && flags.configs[keys.join('.')]) || !configOnly) && (!hasKey(argv, keys) || flags.defaulted[keys.join('.')])) {
+          setArg(keys.join('.'), process.env[envVar])
+        }
+      }
+    })
+  }
+
+  function applyCoercions (argv) {
+    var coerce
+    var applied = {}
+    Object.keys(argv).forEach(function (key) {
+      if (!applied.hasOwnProperty(key)) { // If we haven't already coerced this option via one of its aliases
+        coerce = checkAllAliases(key, flags.coercions)
+        if (typeof coerce === 'function') {
+          try {
+            var value = coerce(argv[key])
+            ;([].concat(flags.aliases[key] || [], key)).forEach(ali => {
+              applied[ali] = argv[ali] = value
+            })
+          } catch (err) {
+            error = err
+          }
+        }
+      }
+    })
+  }
+
+  function setPlaceholderKeys (argv) {
+    flags.keys.forEach((key) => {
+      // don't set placeholder keys for dot notation options 'foo.bar'.
+      if (~key.indexOf('.')) return
+      if (typeof argv[key] === 'undefined') argv[key] = undefined
+    })
+    return argv
+  }
+
+  function applyDefaultsAndAliases (obj, aliases, defaults) {
+    Object.keys(defaults).forEach(function (key) {
+      if (!hasKey(obj, key.split('.'))) {
+        setKey(obj, key.split('.'), defaults[key])
+
+        ;(aliases[key] || []).forEach(function (x) {
+          if (hasKey(obj, x.split('.'))) return
+          setKey(obj, x.split('.'), defaults[key])
+        })
+      }
+    })
+  }
+
+  function hasKey (obj, keys) {
+    var o = obj
+
+    if (!configuration['dot-notation']) keys = [keys.join('.')]
+
+    keys.slice(0, -1).forEach(function (key) {
+      o = (o[key] || {})
+    })
+
+    var key = keys[keys.length - 1]
+
+    if (typeof o !== 'object') return false
+    else return key in o
+  }
+
+  function setKey (obj, keys, value) {
+    var o = obj
+
+    if (!configuration['dot-notation']) keys = [keys.join('.')]
+
+    keys.slice(0, -1).forEach(function (key, index) {
+      // TODO(bcoe): in the next major version of yargs, switch to
+      // Object.create(null) for dot notation:
+      key = sanitizeKey(key)
+
+      if (typeof o === 'object' && o[key] === undefined) {
+        o[key] = {}
+      }
+
+      if (typeof o[key] !== 'object' || Array.isArray(o[key])) {
+        // ensure that o[key] is an array, and that the last item is an empty object.
+        if (Array.isArray(o[key])) {
+          o[key].push({})
+        } else {
+          o[key] = [o[key], {}]
+        }
+
+        // we want to update the empty object at the end of the o[key] array, so set o to that object
+        o = o[key][o[key].length - 1]
+      } else {
+        o = o[key]
+      }
+    })
+
+    // TODO(bcoe): in the next major version of yargs, switch to
+    // Object.create(null) for dot notation:
+    const key = sanitizeKey(keys[keys.length - 1])
+
+    const isTypeArray = checkAllAliases(keys.join('.'), flags.arrays)
+    const isValueArray = Array.isArray(value)
+    let duplicate = configuration['duplicate-arguments-array']
+
+    // nargs has higher priority than duplicate
+    if (!duplicate && checkAllAliases(key, flags.nargs)) {
+      duplicate = true
+      if ((!isUndefined(o[key]) && flags.nargs[key] === 1) || (Array.isArray(o[key]) && o[key].length === flags.nargs[key])) {
+        o[key] = undefined
+      }
+    }
+
+    if (value === increment) {
+      o[key] = increment(o[key])
+    } else if (Array.isArray(o[key])) {
+      if (duplicate && isTypeArray && isValueArray) {
+        o[key] = configuration['flatten-duplicate-arrays'] ? o[key].concat(value) : (Array.isArray(o[key][0]) ? o[key] : [o[key]]).concat([value])
+      } else if (!duplicate && Boolean(isTypeArray) === Boolean(isValueArray)) {
+        o[key] = value
+      } else {
+        o[key] = o[key].concat([value])
+      }
+    } else if (o[key] === undefined && isTypeArray) {
+      o[key] = isValueArray ? value : [value]
+    } else if (duplicate && !(o[key] === undefined || checkAllAliases(key, flags.bools) || checkAllAliases(keys.join('.'), flags.bools) || checkAllAliases(key, flags.counts))) {
+      o[key] = [ o[key], value ]
+    } else {
+      o[key] = value
+    }
+  }
+
+  // extend the aliases list with inferred aliases.
+  function extendAliases (...args) {
+    args.forEach(function (obj) {
+      Object.keys(obj || {}).forEach(function (key) {
+        // short-circuit if we've already added a key
+        // to the aliases array, for example it might
+        // exist in both 'opts.default' and 'opts.key'.
+        if (flags.aliases[key]) return
+
+        flags.aliases[key] = [].concat(aliases[key] || [])
+        // For "--option-name", also set argv.optionName
+        flags.aliases[key].concat(key).forEach(function (x) {
+          if (/-/.test(x) && configuration['camel-case-expansion']) {
+            var c = camelCase(x)
+            if (c !== key && flags.aliases[key].indexOf(c) === -1) {
+              flags.aliases[key].push(c)
+              newAliases[c] = true
+            }
+          }
+        })
+        // For "--optionName", also set argv['option-name']
+        flags.aliases[key].concat(key).forEach(function (x) {
+          if (x.length > 1 && /[A-Z]/.test(x) && configuration['camel-case-expansion']) {
+            var c = decamelize(x, '-')
+            if (c !== key && flags.aliases[key].indexOf(c) === -1) {
+              flags.aliases[key].push(c)
+              newAliases[c] = true
+            }
+          }
+        })
+        flags.aliases[key].forEach(function (x) {
+          flags.aliases[x] = [key].concat(flags.aliases[key].filter(function (y) {
+            return x !== y
+          }))
+        })
+      })
+    })
+  }
+
+  // check if a flag is set for any of a key's aliases.
+  function checkAllAliases (key, flag) {
+    var isSet = false
+    var toCheck = [].concat(flags.aliases[key] || [], key)
+
+    toCheck.forEach(function (key) {
+      if (flag[key]) isSet = flag[key]
+    })
+
+    return isSet
+  }
+
+  function setDefaulted (key) {
+    [].concat(flags.aliases[key] || [], key).forEach(function (k) {
+      flags.defaulted[k] = true
+    })
+  }
+
+  function unsetDefaulted (key) {
+    [].concat(flags.aliases[key] || [], key).forEach(function (k) {
+      delete flags.defaulted[k]
+    })
+  }
+
+  // make a best effor to pick a default value
+  // for an option based on name and type.
+  function defaultValue (key) {
+    if (!checkAllAliases(key, flags.bools) &&
+        !checkAllAliases(key, flags.counts) &&
+        `${key}` in defaults) {
+      return defaults[key]
+    } else {
+      return defaultForType(guessType(key))
+    }
+  }
+
+  // return a default value, given the type of a flag.,
+  // e.g., key of type 'string' will default to '', rather than 'true'.
+  function defaultForType (type) {
+    var def = {
+      boolean: true,
+      string: '',
+      number: undefined,
+      array: []
+    }
+
+    return def[type]
+  }
+
+  // given a flag, enforce a default type.
+  function guessType (key) {
+    var type = 'boolean'
+
+    if (checkAllAliases(key, flags.strings)) type = 'string'
+    else if (checkAllAliases(key, flags.numbers)) type = 'number'
+    else if (checkAllAliases(key, flags.arrays)) type = 'array'
+
+    return type
+  }
+
+  function isNumber (x) {
+    if (x === null || x === undefined) return false
+    // if loaded from config, may already be a number.
+    if (typeof x === 'number') return true
+    // hexadecimal.
+    if (/^0x[0-9a-f]+$/i.test(x)) return true
+    // don't treat 0123 as a number; as it drops the leading '0'.
+    if (x.length > 1 && x[0] === '0') return false
+    return /^[-]?(?:\d+(?:\.\d*)?|\.\d+)(e[-+]?\d+)?$/.test(x)
+  }
+
+  function isUndefined (num) {
+    return num === undefined
+  }
+
+  return {
+    argv: argv,
+    error: error,
+    aliases: flags.aliases,
+    newAliases: newAliases,
+    configuration: configuration
+  }
+}
+
+// if any aliases reference each other, we should
+// merge them together.
+function combineAliases (aliases) {
+  var aliasArrays = []
+  var change = true
+  var combined = {}
+
+  // turn alias lookup hash {key: ['alias1', 'alias2']} into
+  // a simple array ['key', 'alias1', 'alias2']
+  Object.keys(aliases).forEach(function (key) {
+    aliasArrays.push(
+      [].concat(aliases[key], key)
+    )
+  })
+
+  // combine arrays until zero changes are
+  // made in an iteration.
+  while (change) {
+    change = false
+    for (var i = 0; i < aliasArrays.length; i++) {
+      for (var ii = i + 1; ii < aliasArrays.length; ii++) {
+        var intersect = aliasArrays[i].filter(function (v) {
+          return aliasArrays[ii].indexOf(v) !== -1
+        })
+
+        if (intersect.length) {
+          aliasArrays[i] = aliasArrays[i].concat(aliasArrays[ii])
+          aliasArrays.splice(ii, 1)
+          change = true
+          break
+        }
+      }
+    }
+  }
+
+  // map arrays back to the hash-lookup (de-dupe while
+  // we're at it).
+  aliasArrays.forEach(function (aliasArray) {
+    aliasArray = aliasArray.filter(function (v, i, self) {
+      return self.indexOf(v) === i
+    })
+    combined[aliasArray.pop()] = aliasArray
+  })
+
+  return combined
+}
+
+// this function should only be called when a count is given as an arg
+// it is NOT called to set a default value
+// thus we can start the count at 1 instead of 0
+function increment (orig) {
+  return orig !== undefined ? orig + 1 : 1
+}
+
+function Parser (args, opts) {
+  var result = parse(args.slice(), opts)
+
+  return result.argv
+}
+
+// parse arguments and return detailed
+// meta information, aliases, etc.
+Parser.detailed = function (args, opts) {
+  return parse(args.slice(), opts)
+}
+
+// TODO(bcoe): in the next major version of yargs, switch to
+// Object.create(null) for dot notation:
+function sanitizeKey (key) {
+  if (key === '__proto__') return '___proto___'
+  return key
+}
+
+module.exports = Parser
