recursive sum using Array reduce

gistfile1.js

        	var arr = [1,2,3,[4,5,[4,6,[4,5,[5,[5,[6,100,[21]]]]]]]];

        	var result = (function getSum(arr) {
	        	var sum = arr.reduce(function(pre,cur,i,o){
	        		if(typeof cur !== "number") {
	        			return pre + getSum(cur);
	        		}
	        		return pre+cur;
	        	});
        		return sum;
        	})(arr);

        	console.log(result);