recursion

function factorial(num){
	var sum = 1;				

	while(num>0){
		sum *= num;
		num -= 1;
	}
	return sum;
}

function factorialRecursion(num){
	var sum = 1;

	if(num === 0){
		return sum;
	}
	return sum *= factorialRecursion(num-1);
}



function fib(num){
	if(num < 2){
		return 1;
	}
	return (fib(n-1) + fib(n-2));
}


function type(value){
	Object.prototype.toString.call(value).slice(8,-1);
}

function stringify(object){

	type(object) === 'Function'? object + '';
	type(object) === 'Null'? object + '';
	type(object) === 'Boolean'? object + '';
	type(object) === 'Number'? object + '';
	type(object) === 'Undefined'? object + '';
	type(object) === 'String'? '"' + object + '"';

	if(type(object) === 'Array'){
		return '[' + object.map(function(obj){
			return stringify(obj);
		}).join(',') +']';
	}

	if(type(object) === 'Object'){
		var container = [];

		Object.keys(object).forEach(function(key)){
			var value = stringify(object[key]);
			if(value !== null){
				container.push('"' + key + '":' + value);
			}
		};
		return '{' + container.join(',') + '}';
	}
}