perf(computed): clear subscriptions when untracked by all subscribers

Author: johnsoncodehk

lib/computed.ts

@@ -1,4 +1,3 @@
-import { currentEffectScope } from './effectScope';
 import { Dependency, DirtyLevels, Subscriber } from './system';
 
 export function computed<T>(getter: (cachedValue?: T) => T) {
@@ -20,9 +19,7 @@ export class Computed<T = any> implements Dependency, Subscriber {
 
 	constructor(
 		public getter: (cachedValue?: T) => T
-	) {
-		currentEffectScope?.subs.push(this);
-	}
+	) { }
 
 	get(): T {
 		Dependency.link(this);

lib/system.ts

@@ -103,6 +103,7 @@ export namespace Link {
 	}
 
 	export function release(link: Link) {
+		const dep = link.dep as Dependency & ({} | Subscriber);
 		const nextSub = link.nextSub;
 		const prevSub = link.prevSubOrUpdate;
 
@@ -130,6 +131,10 @@ export namespace Link {
 
 		link.nextPropagateOrReleased = pool;
 		pool = link;
+
+		if (dep.subs === undefined && 'deps' in dep) {
+			Subscriber.clearTrack(dep);
+		}
 	}
 }
 
@@ -156,9 +161,7 @@ export namespace Dependency {
 		if (old === undefined || old.dep !== dep) {
 			const newLink = Link.get(dep, sub);
 			if (old !== undefined) {
-				const nextDep = old.nextDep;
-				Link.release(old);
-				newLink.nextDep = nextDep;
+				newLink.nextDep = old;
 			}
 			if (depsTail === undefined) {
 				sub.depsTail = sub.deps = newLink;

tests/effect.spec.ts

@@ -0,0 +1,14 @@
+import { describe, expect, test } from 'vitest';
+import { computed, effect, signal, Subscriber } from '..';
+
+test('should clear subscriptions when untracked by all subscribers', () => {
+	const src = signal(1);
+	const double = computed(() => src.get() * 2);
+	const effect1 = effect(() => {
+		double.get();
+	});
+
+	expect(!!double.subs).toBe(true);
+	Subscriber.clearTrack(effect1);
+	expect(!!double.subs).toBe(false);
+});