wip

packages/core/rxjs-interop/test/to_signal_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {DestroyRef, EnvironmentInjector, Injector, runInInjectionContext} from '@angular/core';
+import {computed, EnvironmentInjector, Injector, runInInjectionContext} from '@angular/core';
 import {toSignal} from '@angular/core/rxjs-interop';
 import {BehaviorSubject, ReplaySubject, Subject} from 'rxjs';
 
@@ -109,6 +109,16 @@ describe('toSignal()', () => {
     expect(counter()).toBe(1);
   });
 
+  fit('should disallow toSignal in computed - WIP', () => {
+    const counter$ = new BehaviorSubject(0);
+    const injector = Injector.create({providers: []}) as EnvironmentInjector;
+    const computedCounter = runInInjectionContext(injector, computed(() => {
+                                                    const counter =
+                                                        toSignal(counter$, {requireSync: true});
+                                                    return counter() * 2;
+                                                  }));
+  });
+
   describe('with no initial value', () => {
     it('should return `undefined` if read before a value is emitted', test(() => {
          const counter$ = new Subject<number>();

packages/core/src/signals/src/computed.ts

@@ -63,10 +63,6 @@ const ERRORED: any = Symbol('ERRORED');
 class ComputedImpl<T> extends ReactiveNode {
   constructor(private computation: () => T, private equal: (oldValue: T, newValue: T) => boolean) {
     super();
-    if (!this.producerReactiveNodesCreationAllowed) {
-      throw new Error(
-          'A new computed signal creation is disallowed in the current reactive context.');
-    }
   }
   /**
    * Current value of the computation.

packages/core/src/signals/src/graph.ts

@@ -92,6 +92,13 @@ interface ReactiveEdge {
  * last observed.
  */
 export abstract class ReactiveNode {
+  constructor() {
+    if (!this.producerReactiveNodesCreationAllowed) {
+      throw new Error(
+          'The current reactive context (usually a computed or an effect) disallow creation of new signals while it is running.');
+    }
+  }
+
   private readonly id = _nextReactiveId++;
 
   /**