From c73d4df2f266113ab8adc5b3140a1a7c8cfbe714 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Fri, 8 Mar 2024 12:05:17 +0100
Subject: [PATCH] Alter atExit to yield callback for removing the hook

---
 packages/core/src/runtime/actor.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/runtime/actor.ts b/packages/core/src/runtime/actor.ts
index 929f7d8..3723668 100644
--- a/packages/core/src/runtime/actor.ts
+++ b/packages/core/src/runtime/actor.ts
@@ -138,8 +138,12 @@ export class Actor {
         return this._dataflowGraph;
     }
 
-    atExit(a: LocalAction): void {
+    atExit(a: LocalAction): () => void {
         this.exitHooks.push(a);
+        return () => {
+            const i = this.exitHooks.indexOf(a);
+            if (i !== -1) this.exitHooks.splice(i, 1);
+        };
     }
 
     _terminateWith(reason: Exclude<ExitReason, null>) {