Genshin Swirl Damage Calculator

swirl.ts

export const debuffResistance = (orig: number, debuff: number) => {
  if (orig < debuff) {
    return -(debuff - orig) / 2;
  } else {
    return orig - debuff;
  }
};

export const swirl = (
  char: {
    level: number;
    em: number;
    reactionBonus: number;
  },
  enemy: { resistance: number; level: number }
) => {
  const baseDmg = [10, 20, 48, 82, 124, 194, 294, 432, 568, 722];
  if (char.level <= 0 || char.level % 10 !== 0) {
    throw new Error("invalid char level");
  }

  const levelMultiplier = baseDmg[char.level / 10];
  const emBonus = (6.66 * char.em) / (char.em + 1400);
  const resMultiplier = 1 - enemy.resistance;
  return (
    levelMultiplier *
    (1 + emBonus + char.reactionBonus) *
    resMultiplier
  );
};