HORIZON PROJECT

(function () {

        "use strict";

        // modified from https://github.com/kriskowal/es5-shim

        var has = Object.prototype.hasOwnProperty,

                toString = Object.prototype.toString,

                forEach = require('./foreach'),

                isArgs = require('./isArguments'),

                hasDontEnumBug = !({'toString': null}).propertyIsEnumerable('toString'),

                hasProtoEnumBug = (function () {}).propertyIsEnumerable('prototype'),

                dontEnums = [

                        "toString",

                        "toLocaleString",

                        "valueOf",

                        "hasOwnProperty",

                        "isPrototypeOf",

                        "propertyIsEnumerable",

                        "constructor"

                ],

                keysShim;

        keysShim = function keys(object) {

                var isObject = object !== null && typeof object === 'object',

                        isFunction = toString.call(object) === '[object Function]',

                        isArguments = isArgs(object),

                        theKeys = [];

                if (!isObject && !isFunction && !isArguments) {

                        throw new TypeError("Object.keys called on a non-object");

                }

                if (isArguments) {

                        forEach(object, function (value) {

                                theKeys.push(value);

                        });

                } else {

                        var name,

                                skipProto = hasProtoEnumBug && isFunction;

                        for (name in object) {

                                if (!(skipProto && name === 'prototype') && has.call(object, name)) {

                                        theKeys.push(name);

                                }

                        }

                }

                if (hasDontEnumBug) {

                        var ctor = object.constructor,

                                skipConstructor = ctor && ctor.prototype === object;

                        forEach(dontEnums, function (dontEnum) {

                                if (!(skipConstructor && dontEnum === 'constructor') && has.call(object, dontEnum)) {

                                        theKeys.push(dontEnum);

                                }

                        });

                }

                return theKeys;

        };

        module.exports = keysShim;

}());