SumPostChecks

type SumPostChecks<A extends number, B extends number, AreNegative = [IsNegative<A>, IsNegative<B>]> = AreNegative extends [false, false] // When both numbers are positive we can add them together ? SumPositives<A, B> : AreNegative extends [true, true] // When both numbers are negative we add the absolute values and then reverse the sign ? ReverseSign<SumPositives<Absolute<A>, Absolute<B>>> // When the signs are different we can subtract the absolute values, remove the sign // and then reverse the sign if the larger absolute value is negative : Absolute<Subtract<Absolute<A>, Absolute<B>>> extends infer Result extends number ? TupleMax<[Absolute<A>, Absolute<B>]> extends infer Max_ extends number ? Max_ extends A | B // The larger absolute value is positive, so the result is positive ? Result // The larger absolute value is negative, so the result is negative : ReverseSign<Result> : never : never

type SumPostChecks<A extends number, B extends number, AreNegative = [IsNegative<A>, IsNegative<B>]> = AreNegative extends [false, false] // When both numbers are positive we can add them together ? SumPositives<A, B> : AreNegative extends [true, true] // When both numbers are negative we add the absolute values and then reverse the sign ? ReverseSign<SumPositives<Absolute<A>, Absolute<B>>> // When the signs are different we can subtract the absolute values, remove the sign // and then reverse the sign if the larger absolute value is negative : Absolute<Subtract<Absolute<A>, Absolute<B>>> extends infer Result extends number ? TupleMax<[Absolute<A>, Absolute<B>]> extends infer Max_ extends number ? Max_ extends A | B // The larger absolute value is positive, so the result is positive ? Result // The larger absolute value is negative, so the result is negative : ReverseSign<Result> : never : never