Custom waitFor timeout error

source/errors.ts

@@ -0,0 +1,9 @@
+/**
+ * Error thrown when a waitFor timeout is reached
+ */
+export class WaitForTimeoutError extends Error {
+    constructor(type: string) {
+        super(`Timeout waiting for event "${type}"`);
+        this.name = 'WaitForTimeoutError';
+    }
+}

source/event-emitter.ts

@@ -1,5 +1,6 @@
 import type { DeeplyReadonly } from './types.ts';
 
+import { WaitForTimeoutError } from './errors.ts';
 import { deepFreeze } from './misc.ts';
 
 export type EventMap = Record<string, unknown>;
@@ -213,7 +214,7 @@ export class EventEmitter<T extends EventMap> {
             if (timeoutMs !== undefined) {
                 timeoutId = setTimeout(() => {
                     this.off(type, listener);
-                    reject(new Error(`Timeout waiting for event "${String(type)}"`));
+                    reject(new WaitForTimeoutError(String(type)));
                 }, timeoutMs);
             }