"use strict";

function mod10(number) {
	var sum = 0;
	for (var i = 0; i < number.length; i++) {
		var n = parseInt(number[i]);
		if ((i + number.length) % 2 === 0) {
			sum += n;
		} else {
			sum += n * 2 % 10 + Math.floor(n * 2 / 10);
		}
	}
	return (10 - sum % 10) % 10;
}

function mod11(number) {
	var sum = 0;
	var weights = [2, 3, 4, 5, 6, 7];
	for (var i = 0; i < number.length; i++) {
		var n = parseInt(number[number.length - 1 - i]);
		sum += weights[i % weights.length] * n;
	}
	return (11 - sum % 11) % 11;
}

export default {
	mod10,
	mod11
}