index.js

exports.sex = function(ascendancyNum){
	if(validNumber(ascendancyNum) == false){
		return "error";
	} 
	var gender = undefined;
	
	if(ascendancyNum % 2 == 1) {
        gender = 'female';
        ascendancyNum -= 1;
    } else {
        gender = 'male';
    }
    return gender;
};

exports.line = function (ascendancyNum){
	
	if(validNumber(ascendancyNum) == false){
		return "error";
	} 
    
    var line = checkLine(ascendancyNum);
	// If the number is already 1,2, or 3, no further calculations need to be run. 
	// Higher or missing numbers return as "undetermined"
    
    if(line != 'undetermined') {
        return line;
    } else {
        //If the number is odd, subtract 1, unless the number is 3 because that 
        //	means the mother's line and that is as far as this should go. 
        //Otherwise it returns everyone as fathersLine
        //	The loop always returns 1,2,3 or undetermined
        for(i = ascendancyNum; line == 'undetermined'; i /= 2) {
            if(i % 2 == 1 && i != 3) {
                i -= 1;
            }
            line = checkLine(i);
        }
        return line;
    }
};

exports.fullLine = function(ascendancyNum) {
	if(validNumber(ascendancyNum) == false){
		return "error";
	} 
	var ascendancy = [];
	var i = ascendancyNum;
	
        //M = Mother, F = Father
        //This loop calculates like the one in exports.line
        do {
            if(i % 2 == 1) {
                ascendancy.splice(0,0,"M");
                if(i > 3){
                	i -= 1;
                }
        	} else if(i % 2 == 0){
        		ascendancy.splice(0,0,"F");
        	} else {
        		throw "The ascendancy path can only be generated for Ahnen numbers higher than 1.";
        	}
        	i /= 2;
		}
		while(i >= 2);
		
		return ascendancy;
};

var checkLine = function(ascendancyNum) {
    
        switch(ascendancyNum) {
        case 1: 
            return 'rootPerson';
            
        case 2: 
            return 'fathersLine';
            
        case 3:
            return 'mothersLine';
            
        default:
            return 'undetermined';
        }
    
};

var validNumber = function(ascendancyNum){
	if(Number.isInteger(ascendancyNum) === false || ascendancyNum <= 0){
		return false;
	} else {return true;}
};