From 4d0cc4b2f792f9b5cacb2e06c48e1ff01e6cbc2b Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Mon, 18 Dec 2023 10:32:37 +1300
Subject: [PATCH] Deduplicate subject updates. Fixes #3.

---
 packages/core/src/runtime/dataflow.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/core/src/runtime/dataflow.ts b/packages/core/src/runtime/dataflow.ts
index b980bb5..141a2b2 100644
--- a/packages/core/src/runtime/dataflow.ts
+++ b/packages/core/src/runtime/dataflow.ts
@@ -95,10 +95,14 @@ export class Graph<SubjectId, ObjectId> implements ObservingGraph<ObjectId> {
 
             if (workSet.size === 0) break;
 
+            const updatedSubjects = new FlexSet(this.subjectIdCanonicalizer);
             workSet.forEach(objectId => {
                 this.observersOf(objectId).forEach((subjectId: SubjectId) => {
-                    this.forgetSubject(subjectId);
-                    this.withSubject(subjectId, () => repairNode(subjectId));
+                    if (!updatedSubjects.has(subjectId)) {
+                        updatedSubjects.add(subjectId);
+                        this.forgetSubject(subjectId);
+                        this.withSubject(subjectId, () => repairNode(subjectId));
+                    }
                 });
             });
         }