var passwordGen = len => {
	len = len || 20;
	var keyArr = "~!@#$%^&*()_+{}:\"<> 1234567890QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm,./;\'[]\\".split("");

	function startGen(tmp){
		for(let i = 0 ; i< len ; i++)
			tmp += keyArr[parseInt(Math.random() * 91)];

		var atLast = (len/4) - parseInt(Math.sqrt(len/4));
		var signCount = 0, upper = 0 , lower = 0 , number = 0;

		for(let i of tmp){
			if("~!@#$%^&*()_+{}:\"<> ,./;\'[]\\".indexOf(i) > 0) signCount++;
			if("1234567890".indexOf(i) > 0) number++;
			if("QWERTYUIOPASDFGHJKLZXCVBNM".indexOf(i) > 0) upper++;
			if("qwertyuiopasdfghjklzxcvbnm".indexOf(i) > 0) lower++;
		}

		if(signCount < atLast || upper < atLast || lower < atLast || number < atLast)
			return startGen("");
		else return tmp;
	}

	return startGen("");
}