31 lines
945 B
TypeScript
31 lines
945 B
TypeScript
import { proficiencyBonus } from "./creature-types.js";
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export interface InitiativeResult {
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readonly modifier: number;
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readonly passive: number;
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}
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/**
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* Calculates initiative modifier and passive initiative from creature stats.
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* Returns undefined for combatants without bestiary creature data.
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*/
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export function calculateInitiative(creature: {
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readonly dexScore: number;
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readonly cr: string;
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readonly initiativeProficiency: number;
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}): InitiativeResult {
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const dexMod = Math.floor((creature.dexScore - 10) / 2);
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const pb = proficiencyBonus(creature.cr);
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const modifier = dexMod + (creature.initiativeProficiency ?? 0) * pb;
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return { modifier, passive: 10 + modifier };
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}
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/**
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* Formats an initiative modifier with explicit sign.
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* Uses U+2212 (−) for negative values.
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*/
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export function formatInitiativeModifier(modifier: number): string {
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if (modifier >= 0) return `+${modifier}`;
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return `\u2212${Math.abs(modifier)}`;
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}
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