Walk a javascript hash recursive and check for key exists

gistfile1.js

var a = { a: { b: 1 } };
var b = ['a','b'];

var hashKeyExists = function(obj,path){

	var keys = path.split('.');
	
	var keyExists = function(obj,keyList){

		var cur = keyList.shift();
	
		if(obj.hasOwnProperty(cur)){
			if(keyList.length<=0){
				return true;
			}else{
				return keyExists(obj[cur],keyList);
			}
		}else{
			return false;
		}	
	};
	
	if(obj && typeof obj == "object" && keys.length>0){
		return keyExists(obj,keys);
	}else{
		return false;
		
	}
}

// Test cases - for chrome console
assert(hashKeyExists(a,'a.b')==true,'the key´s should exist');
assert(hashKeyExists(a,'a.b.')==false,'the key should not exist');
assert(hashKeyExists(a,'a')==true,'the key should exist');
assert(hashKeyExists(a,'a.b.c')==false,'the key should not exist');
assert(hashKeyExists(null,'a.b.c')==false,'return value should be false not a valid has');