fix: pool.destroy to clean up async resources (#86)

src/index.ts

@@ -1161,8 +1161,9 @@ class Tinypool extends EventEmitterAsyncResource {
     })
   }
 
-  destroy() {
-    return this.#pool.destroy()
+  async destroy() {
+    await this.#pool.destroy()
+    this.emitDestroy()
   }
 
   get options(): FilledOptions {

test/pool-destroy.test.ts

@@ -1,10 +1,8 @@
+import { createHook } from 'async_hooks'
 import { dirname, resolve } from 'path'
 import { Tinypool } from 'tinypool'
 import { fileURLToPath } from 'url'
 
-const sleep = async (num: number) =>
-  await new Promise((res) => setTimeout(res, num))
-
 const __dirname = dirname(fileURLToPath(import.meta.url))
 
 test('can destroy pool while tasks are running', async () => {
@@ -24,3 +22,45 @@ test('destroy after initializing should work (#43)', async () => {
   expect(pool.run({})).rejects.toThrow(/Terminating worker thread/)
   setImmediate(() => pool.destroy())
 })
+
+test('cleans up async resources', async () => {
+  let onCleanup = () => {}
+  const waitForCleanup = new Promise<void>((r) => (onCleanup = r))
+  const timeout = setTimeout(() => {
+    throw new Error('Timeout waiting for async resource destroying')
+  }, 2_000).unref()
+
+  const ids = new Set<number>()
+
+  const hook = createHook({
+    init(asyncId, type) {
+      if (type === 'Tinypool') {
+        ids.add(asyncId)
+      }
+    },
+    destroy(asyncId) {
+      if (ids.has(asyncId)) {
+        ids.delete(asyncId)
+        onCleanup()
+        clearTimeout(timeout)
+      }
+    },
+  })
+  hook.enable()
+
+  const pool = new Tinypool({
+    filename: resolve(__dirname, 'fixtures/eval.js'),
+    maxThreads: 1,
+    minThreads: 1,
+  })
+
+  await pool.run('42')
+
+  expect(ids.size).toBe(1)
+
+  await pool.destroy()
+  await waitForCleanup
+
+  expect(ids.size).toBe(0)
+  hook.disable()
+})