weapon damage calculations

src/damage.ts

@@ -0,0 +1,67 @@
+import { Element } from "kolmafia";
+import { $elements } from "./template-string.js";
+import { get as getModifier } from "./modifier.js";
+import { capitalize, sum } from "./utils.js";
+
+export const SUPER_EFFECTIVE_CHART = Object.freeze({
+  hot: $elements`Spooky, Cold`,
+  spooky: $elements`Cold, Sleaze`,
+  cold: $elements`Sleaze, Stench`,
+  sleaze: $elements`Stench, Hot`,
+  stench: $elements`Hot, Spooky`,
+} as const);
+
+function isConventionalElement(
+  name: string,
+): name is keyof typeof SUPER_EFFECTIVE_CHART {
+  return name in SUPER_EFFECTIVE_CHART;
+}
+
+/**
+ * Determines if one type deals super effective damage against the other
+ * @param element The type of the damage
+ * @param against The type of the monster
+ * @returns Whether `element` is super effective against `against`
+ */
+export function isSuperEffective(element: Element, against: Element): boolean {
+  const elementName = element.toString();
+
+  return (
+    isConventionalElement(elementName) &&
+    SUPER_EFFECTIVE_CHART[elementName].includes(against)
+  );
+}
+
+/**
+ * Determines the amount of expected elemental damage, taking into account immunity and super effectiveness.
+ * @param damage The base amount of damage
+ * @param damageType The elemental type of the damage
+ * @param monsterType The elemental type of the target
+ * @returns The expected amount of damage the target would take
+ */
+export function elementalDamage(
+  damage: number,
+  damageType: Element,
+  monsterType: Element,
+): number {
+  if (damage === 0) return 0;
+  if (damageType === monsterType) return 1;
+  if (isSuperEffective(damageType, monsterType)) return 2 * damage;
+  return damage;
+}
+
+export const TRADITIONAL_ELEMENTS = Object.freeze(
+  $elements`cold, hot, sleaze, spooky, stench`,
+);
+
+/**
+ * @returns The total amount of elemental damage you have from all sources
+ */
+export function totalElementalDamage(): number {
+  return sum(
+    TRADITIONAL_ELEMENTS.map((el) => el.toString()).filter(
+      isConventionalElement,
+    ),
+    (el) => getModifier(`${capitalize(el)} Damage`),
+  );
+}

src/utils.ts

@@ -410,6 +410,9 @@ export type Range<A extends number, B extends number> = Exclude<
   Enumerate<A>
 >;
 
+export const capitalize = <T extends string>(str: T): Capitalize<T> =>
+  (str.length ? `${str[0].toUpperCase()}${str.slice(1)}` : "") as Capitalize<T>;
+
 /**
  * Translate mafia's multi-dimensional array prefs into a multi-dimensional array
  * @param prop The property (or whatever) to process; not the property NAME, the value itself
@@ -436,3 +439,4 @@ export function multiSplit<T extends any[]>(
     mappers.map((func, index) => func(tup[index])),
   ) as T[];
 }
+