Shuffle and global flatten for arrays

var arr = [1, 2, 4, 7, 9, 6, 3];

function flatten() {
    return [].reduce.call(arguments, function(sum, val) {
        return Array.isArray(val) ? sum.concat(flatten.apply(null, val)) : sum.concat(val);
    }, []);
}

function shuffle (array) {
	var temp = [];

	while (0 !== array.length) {
		temp.push(array.splice(Math.floor(Math.random() * (array.length -1)), 1 ) );
	}

	return flatten(temp);
}

console.log(shuffle(arr))