feat(signal-store): reimplement toObservable with Subject instead of …

…ReplaySubject
spierala · Oct 25, 2023 · c8f6609 · c8f6609
1 parent b177427
commit c8f6609
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Showing 4 changed files with 64 additions and 4 deletions.
diff --git a/LICENSE b/LICENSE
@@ -63,3 +63,7 @@ See the file for details.
 This repository includes a file "deep-freeze.ts" originally copied from
 https://github.com/jsdf/deep-freeze/blob/v1.1.1/index.js, public domain licensed.
 See the file for details.
+
+This repository includes a file "mini-rx-to-observable.ts" originally copied from
+https://github.com/angular/angular/blob/16.2.10/packages/core/rxjs-interop/src/take_until_destroyed.ts, MIT style licensed.
+See the file for details.
diff --git a/libs/signal-store/src/lib/connect.ts b/libs/signal-store/src/lib/connect.ts
@@ -1,8 +1,9 @@
 import { DestroyRef, EnvironmentInjector, inject, Signal } from '@angular/core';
-import { takeUntilDestroyed, toObservable } from '@angular/core/rxjs-interop';
+import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
 import { Observable } from 'rxjs';
 import { Action, OperationType, StateOrCallback } from '@mini-rx/common';
 import { miniRxIsSignal } from './utils';
+import { miniRxToObservable } from './mini-rx-to-observable';
 
 export function createConnectFn<StateType>(
     dispatch: (
@@ -22,7 +23,7 @@ export function createConnectFn<StateType>(
         keys.forEach((key) => {
             const observableOrSignal: Observable<ValueType> | Signal<ValueType> = dict[key];
             const obs$ = miniRxIsSignal(observableOrSignal)
-                ? toObservable(observableOrSignal, { injector })
+                ? miniRxToObservable(observableOrSignal, { injector })
                 : observableOrSignal;
             obs$.pipe(takeUntilDestroyed(destroyRef)).subscribe((v) => {
                 dispatch(

diff --git a/libs/signal-store/src/lib/mini-rx-to-observable.ts b/libs/signal-store/src/lib/mini-rx-to-observable.ts
@@ -0,0 +1,54 @@
+// Credits go to Angular
+// Copied from with small modifications: https://github.com/angular/angular/blob/16.2.10/packages/core/rxjs-interop/src/take_until_destroyed.ts
+
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {
+    assertInInjectionContext,
+    DestroyRef,
+    effect,
+    inject,
+    Injector,
+    Signal,
+    untracked,
+} from '@angular/core';
+import { ToObservableOptions } from '@angular/core/rxjs-interop';
+import { Observable, Subject } from 'rxjs';
+
+// Reimplemented `toObservable` from Angular
+// Use Subject instead of ReplaySubject (which is more lightweight and sufficient for internal use in MiniRx)
+export function miniRxToObservable<T>(
+    source: Signal<T>,
+    options?: ToObservableOptions
+): Observable<T> {
+    !options?.injector && assertInInjectionContext(miniRxToObservable);
+    const injector = options?.injector ?? inject(Injector);
+    const subject = new Subject<T>();
+
+    const watcher = effect(
+        () => {
+            let value: T;
+            try {
+                value = source();
+            } catch (err) {
+                untracked(() => subject.error(err));
+                return;
+            }
+            untracked(() => subject.next(value));
+        },
+        { injector, manualCleanup: true }
+    );
+
+    injector.get(DestroyRef).onDestroy(() => {
+        watcher.destroy();
+        subject.complete();
+    });
+
+    return subject.asObservable();
+}
diff --git a/libs/signal-store/src/lib/rx-effect.ts b/libs/signal-store/src/lib/rx-effect.ts
@@ -1,8 +1,9 @@
 import { DestroyRef, inject, Signal } from '@angular/core';
-import { takeUntilDestroyed, toObservable } from '@angular/core/rxjs-interop';
+import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
 import { isObservable, Observable, Subject } from 'rxjs';
 import { defaultEffectsErrorHandler } from '@mini-rx/common';
 import { miniRxIsSignal } from './utils';
+import { miniRxToObservable } from './mini-rx-to-observable';
 
 export function createRxEffectFn() {
     const destroyRef = inject(DestroyRef);
@@ -33,7 +34,7 @@ export function createRxEffectFn() {
         ) => {
             // If we detect a Signal: convert Signal to Observable
             observableOrValue = miniRxIsSignal(observableOrValue)
-                ? toObservable(observableOrValue)
+                ? miniRxToObservable(observableOrValue)
                 : observableOrValue;
 
             isObservable(observableOrValue)