Fix.

node_modules/yargs/lib/argsert.js

@@ -0,0 +1,66 @@
+'use strict'
+const command = require('./command')()
+const YError = require('./yerror')
+
+const positionName = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth']
+
+module.exports = function argsert (expected, callerArguments, length) {
+  // TODO: should this eventually raise an exception.
+  try {
+    // preface the argument description with "cmd", so
+    // that we can run it through yargs' command parser.
+    let position = 0
+    let parsed = {demanded: [], optional: []}
+    if (typeof expected === 'object') {
+      length = callerArguments
+      callerArguments = expected
+    } else {
+      parsed = command.parseCommand(`cmd ${expected}`)
+    }
+    const args = [].slice.call(callerArguments)
+
+    while (args.length && args[args.length - 1] === undefined) args.pop()
+    length = length || args.length
+
+    if (length < parsed.demanded.length) {
+      throw new YError(`Not enough arguments provided. Expected ${parsed.demanded.length} but received ${args.length}.`)
+    }
+
+    const totalCommands = parsed.demanded.length + parsed.optional.length
+    if (length > totalCommands) {
+      throw new YError(`Too many arguments provided. Expected max ${totalCommands} but received ${length}.`)
+    }
+
+    parsed.demanded.forEach((demanded) => {
+      const arg = args.shift()
+      const observedType = guessType(arg)
+      const matchingTypes = demanded.cmd.filter(type => type === observedType || type === '*')
+      if (matchingTypes.length === 0) argumentTypeError(observedType, demanded.cmd, position, false)
+      position += 1
+    })
+
+    parsed.optional.forEach((optional) => {
+      if (args.length === 0) return
+      const arg = args.shift()
+      const observedType = guessType(arg)
+      const matchingTypes = optional.cmd.filter(type => type === observedType || type === '*')
+      if (matchingTypes.length === 0) argumentTypeError(observedType, optional.cmd, position, true)
+      position += 1
+    })
+  } catch (err) {
+    console.warn(err.stack)
+  }
+}
+
+function guessType (arg) {
+  if (Array.isArray(arg)) {
+    return 'array'
+  } else if (arg === null) {
+    return 'null'
+  }
+  return typeof arg
+}
+
+function argumentTypeError (observedType, allowedTypes, position, optional) {
+  throw new YError(`Invalid ${positionName[position] || 'manyith'} argument. Expected ${allowedTypes.join(' or ')} but received ${observedType}.`)
+}