将类数组arguments转化成数组

一、将arguments对象绑定到slice方法上

二、 例子：

//闭包 二次封装函数 求和
function partialUsingArguments(fn) {
	var args = Array.prototype.slice.call(arguments, 1);
        var result  = function () {
    	var args2 = Array.prototype.slice.call(arguments);
    	args = args.concat(args2);
        return  fn.apply(this, args);

    }
    return result;
}

var a = 1; var b = 2; var c = 3; var d = 4;
var test = function (first, second, third, forth) {
    return first + second + third + forth;
};
console.log("1+2+3+4="+ partialUsingArguments(test, a, b)(c, d) );