is_arguments.js

var supportsArgumentsClass = (function(){
  return Object.prototype.toString.call(arguments)
})() == '[object Arguments]';

exports = module.exports = supportsArgumentsClass ? supported : unsupported;

exports.supported = supported;
function supported(object) {
  return Object.prototype.toString.call(object) == '[object Arguments]';
};

exports.unsupported = unsupported;
function unsupported(object){
  return object &&
    typeof object == 'object' &&
    typeof object.length == 'number' &&
    Object.prototype.hasOwnProperty.call(object, 'callee') &&
    !Object.prototype.propertyIsEnumerable.call(object, 'callee') ||
    false;
};