Add enemy pools and getNodeEnemy by node type

src/map.js

@@ -1,3 +1,15 @@
+const ENCOUNTER_POOL = [
+  "jaw_worm",
+  "cultist",
+  "fungi_beast",
+  "small_slime",
+  "red_louse",
+  "green_louse",
+  "blue_slaver",
+];
+const ELITE_POOL = ["lagavulin", "gremlin_nob", "sentry"];
+const BOSS_POOL = ["slime_boss", "the_guardian"];
+
 const ACT1_LAYOUT = [
   "encounter",
   "encounter",
@@ -33,3 +45,14 @@ export function advanceMap(map) {
 export function getCurrentNode(map) {
   return map.nodes[map.currentNode];
 }
+
+export function getNodeEnemy(nodeType) {
+  const pools = {
+    encounter: ENCOUNTER_POOL,
+    elite: ELITE_POOL,
+    boss: BOSS_POOL,
+  };
+  const pool = pools[nodeType];
+  if (!pool) return null;
+  return pool[Math.floor(Math.random() * pool.length)];
+}

src/map.test.js

@@ -1,5 +1,5 @@
 import { describe, expect, test } from "bun:test";
-import { advanceMap, createMap, getCurrentNode } from "./map.js";
+import { advanceMap, createMap, getCurrentNode, getNodeEnemy } from "./map.js";
 
 describe("createMap", () => {
   test("returns 10 nodes", () => {
@@ -79,3 +79,48 @@ describe("getCurrentNode", () => {
     expect(node.id).toBe(1);
   });
 });
+
+const ENCOUNTER_POOL = [
+  "jaw_worm",
+  "cultist",
+  "fungi_beast",
+  "small_slime",
+  "red_louse",
+  "green_louse",
+  "blue_slaver",
+];
+const ELITE_POOL = ["lagavulin", "gremlin_nob", "sentry"];
+const BOSS_POOL = ["slime_boss", "the_guardian"];
+
+describe("getNodeEnemy", () => {
+  test("encounter returns an id from the encounter pool", () => {
+    const enemy = getNodeEnemy("encounter");
+    expect(ENCOUNTER_POOL).toContain(enemy);
+  });
+
+  test("elite returns an id from the elite pool", () => {
+    const enemy = getNodeEnemy("elite");
+    expect(ELITE_POOL).toContain(enemy);
+  });
+
+  test("boss returns an id from the boss pool", () => {
+    const enemy = getNodeEnemy("boss");
+    expect(BOSS_POOL).toContain(enemy);
+  });
+
+  test("campfire returns null", () => {
+    expect(getNodeEnemy("campfire")).toBeNull();
+  });
+
+  test("unknown type returns null", () => {
+    expect(getNodeEnemy("shop")).toBeNull();
+  });
+
+  test("encounter pool has randomness across 50 calls", () => {
+    const results = new Set();
+    for (let i = 0; i < 50; i++) {
+      results.add(getNodeEnemy("encounter"));
+    }
+    expect(results.size).toBeGreaterThan(1);
+  });
+});