// Internal method, used by iteration functions.
// Calls a function for each key-value pair found in object
// Optionally takes compareFn to iterate object in specific order

"use strict";

var callable                = require("./valid-callable")
  , value                   = require("./valid-value")
  , bind                    = Function.prototype.bind
  , call                    = Function.prototype.call
  , keys                    = Object.keys
  , objPropertyIsEnumerable = Object.prototype.propertyIsEnumerable;

module.exports = function (method, defVal) {
	return function (obj, cb/*, thisArg, compareFn*/) {
		var list, thisArg = arguments[2], compareFn = arguments[3];
		obj = Object(value(obj));
		callable(cb);

		list = keys(obj);
		if (compareFn) {
			list.sort(typeof compareFn === "function" ? bind.call(compareFn, obj) : undefined);
		}
		if (typeof method !== "function") method = list[method];
		return call.call(method, list, function (key, index) {
			if (!objPropertyIsEnumerable.call(obj, key)) return defVal;
			return call.call(cb, thisArg, obj[key], key, obj, index);
		});
	};
};