change: descriptive pool acquire timeout error message (#57)

Author: Gianluca-Casagrande-Stiga

src/Deferred.ts

@@ -1,5 +1,8 @@
 import { TimeoutError } from './TimeoutError';
 
+interface DeferredOptions {
+  errorMessage?: string;
+}
 /**
  * Deferred Implementation
  *
@@ -10,8 +13,10 @@ export class Deferred<T> {
   protected _resolve: (value: T) => void;
   protected _reject: (error: Error) => void;
   protected _timeout: NodeJS.Timer;
+  private options: DeferredOptions;
 
-  constructor() {
+  constructor(options: DeferredOptions = {}) {
+    this.options = options;
     this._promise = new Promise((resolve, reject) => {
       this._reject = reject;
       this._resolve = resolve;
@@ -23,7 +28,9 @@ export class Deferred<T> {
 
     this._timeout = setTimeout(() => {
       callback();
-      this.reject(new TimeoutError('Operation timeout'));
+      this.reject(
+        new TimeoutError(this.options.errorMessage ?? 'Operation timeout'),
+      );
     }, timeoutInMillis);
   }
 

src/Pool.ts

@@ -433,7 +433,9 @@ export class Pool<RawResource> {
       );
     }
 
-    const deferred = new Deferred<RawResource>();
+    const deferred = new Deferred<RawResource>({
+      errorMessage: 'Pool acquire operation timeout',
+    });
     deferred.registerTimeout(this.acquireTimeoutMillis, () => {
       // timeout triggered, promise will be rejected
       // remove this object from pending list

test/integration/pool-test.ts

@@ -23,7 +23,7 @@ tap.test('pool expands only to max limit', (t) => {
     .then((obj) => {
       return pool.acquire().catch((e) => {
         t.ok(e instanceof TimeoutError);
-        t.ok(e.message === 'Operation timeout');
+        t.ok(e.message === 'Pool acquire operation timeout');
         pool.release(obj);
         t.end();
       });