N3-components/N3-components

// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.

function isArray (arg) {
  if (Array.isArray) {
    return Array.isArray(arg)
  }
  return objectToString(arg) === '[object Array]'
}
exports.isArray = isArray

function isBoolean (arg) {
  return typeof arg === 'boolean'
}
exports.isBoolean = isBoolean

function isNull (arg) {
  return arg === null
}
exports.isNull = isNull

function isNullOrUndefined (arg) {
  return arg == null
}
exports.isNullOrUndefined = isNullOrUndefined

function isNumber (arg) {
  return typeof arg === 'number'
}
exports.isNumber = isNumber

function isString (arg) {
  return typeof arg === 'string'
}
exports.isString = isString

function isSymbol (arg) {
  return typeof arg === 'symbol'
}
exports.isSymbol = isSymbol

function isUndefined (arg) {
  return arg === void 0
}
exports.isUndefined = isUndefined

function isRegExp (re) {
  return objectToString(re) === '[object RegExp]'
}
exports.isRegExp = isRegExp

function isObject (arg) {
  return typeof arg === 'object' && arg !== null
}
exports.isObject = isObject

function isDate (d) {
  return objectToString(d) === '[object Date]'
}
exports.isDate = isDate

function isError (e) {
  return (objectToString(e) === '[object Error]' || e instanceof Error)
}
exports.isError = isError

function isFunction (arg) {
  return typeof arg === 'function'
}
exports.isFunction = isFunction

function isPrimitive (arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined'
}
exports.isPrimitive = isPrimitive

function objectToString (o) {
  return Object.prototype.toString.call(o)
}

function isPromise (promise) {
  return isObject(promise) && isFunction(promise.then) && isFunction(promise.catch)
}
exports.isPromise = isPromise