From 504540df71e46378b72addd0b09f11dd966f820f Mon Sep 17 00:00:00 2001
From: Sadie Dotzler <sadiedotzler@gmail.com>
Date: Mon, 27 Jun 2022 22:33:44 -0700
Subject: [PATCH 1/3] fix inconsistent naming

---
 test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test.ts b/test.ts
index 5bcbb18..c8c615f 100644
--- a/test.ts
+++ b/test.ts
@@ -171,7 +171,7 @@ Deno.test("closeMixed", async () => {
     }
   })();
 
-  for await (const x of ee) {
+  for await (const _ of ee) {
     await ee.off();
   }
 });

From 577d5a0a3101a70a3908c46996bfb2f05d4b2f40 Mon Sep 17 00:00:00 2001
From: Sadie Dotzler <sadiedotzler@gmail.com>
Date: Mon, 27 Jun 2022 23:01:47 -0700
Subject: [PATCH 2/3] implement wait method

---
 mod.ts | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/mod.ts b/mod.ts
index d397aa6..c4bde87 100644
--- a/mod.ts
+++ b/mod.ts
@@ -9,7 +9,7 @@ export class EventEmitter<E extends Record<string, unknown[]>> {
   #listeners: {
     [K in keyof E]?: Array<{
       once: boolean;
-      cb: (...args: E[K]) => void;
+      cb: (...args: E[K]) => void | Promise<void>;
     }>;
   } = {};
   #globalWriters: WritableStreamDefaultWriter<Entry<E, keyof E>>[] = [];
@@ -183,6 +183,26 @@ export class EventEmitter<E extends Record<string, unknown[]>> {
     }
   }
 
+  /**
+   * Call and, if async, await the completion of the listeners registered for
+   * the event named eventName, in the order they were registered, passing the
+   * supplied arguments to each. Returns a Promise that resolves on the completion
+   * of the last listener.
+   *
+   * Does not support being awaited the same was as `emit`.
+   */
+  async wait<K extends keyof E>(eventName: K, ...args: E[K]): Promise<void> {
+    const listeners = this.#listeners[eventName]?.slice() ?? [];
+    for (const { cb, once } of listeners) {
+      const ret = cb(...args);
+      if (ret) await ret;
+
+      if (once) {
+        this.off(eventName, cb);
+      }
+    }
+  }
+
   [Symbol.asyncIterator]<K extends keyof E>(): AsyncIterableIterator<
     { [V in K]: Entry<E, V> }[K]
   > {

From 9c56011a78e93b731213a8e10dcc9bf1324921c4 Mon Sep 17 00:00:00 2001
From: Sadie Dotzler <sadiedotzler@gmail.com>
Date: Mon, 27 Jun 2022 23:06:28 -0700
Subject: [PATCH 3/3] add test for wait method

---
 test.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/test.ts b/test.ts
index c8c615f..708f9f7 100644
--- a/test.ts
+++ b/test.ts
@@ -182,3 +182,17 @@ Deno.test("limitReached", () => {
   ee.on("foo", () => {});
   assertThrows(() => ee.on("foo", () => {}));
 });
+
+Deno.test("wait", async () => {
+  const ee = new EventEmitter<Events>();
+
+  ee.on("foo", async () => {
+    console.log("foo");
+    await new Promise((resolve) => setTimeout(resolve, 1000));
+  }).on("bar", () => {
+    console.log("bar");
+  });
+
+  await ee.wait("foo", "baz");
+  await ee.wait("bar", 0);
+});