export class Utils { static moduloSum = ( a , b , divisor , offset = 0 , subtraction = false ) : number => { let dividend = ( subtraction ) ? ( ( a - offset ) - ( b - offset ) ) : ( ( a - offset ) + ( b - offset ) ) ; return Utils . modulo ( dividend , divisor ) + offset ; } ; static modulo = ( a , b ) : number => { return ( ( a % b ) + b ) % b ; } ; }