Map function, callback exercise

map.js

var map = function(list, callback) {
	var arrList = [];
	
	if (!list) {
		throw new Error('Error, list is undefined');
	}
	
	if (list.constructor === Array && list[0].constructor === Object) {
		
		for(var i = 0; i < list.length; i++) {
			return callback(list[i]);
		}
		
	} else if (list.constructor === Array) {
		
		for (var e = 0; e < list.length; e++) {
  			arrList.push(callback(list[e]));
		}
		
		return arrList;
	}
};

var arr = [22,32]

map(arr, function(item) {
	return item * 2; // returns [44, 64]
});