feat(signals): extend symbol support

Following functions support symbols:
- `withState`
- `withMethods`
- `withComputed`
- Slices (`DeepSignal`)
- `deepFreeze`
- override protection

modules/signals/spec/deep-freeze.spec.ts

@@ -5,6 +5,9 @@ import { TestBed } from '@angular/core/testing';
 import { withState } from '../src/with-state';
 
 describe('deepFreeze', () => {
+  const DIRECT_SECRET = Symbol('direct secret');
+  const SECRET = Symbol('secret');
+
   const initialState = {
     user: {
       firstName: 'John',
@@ -13,6 +16,14 @@ describe('deepFreeze', () => {
     foo: 'bar',
     numbers: [1, 2, 3],
     ngrx: 'signals',
+    [DIRECT_SECRET]: 'secret',
+    nestedSymbol: {
+      [SECRET]: 'another secret',
+    },
+    [SECRET]: {
+      code: 'secret',
+      value: '123',
+    },
   };
 
   for (const { stateFactory, name } of [
@@ -71,7 +82,7 @@ describe('deepFreeze', () => {
           );
         });
 
-        it('throws when mutable change happens for', () => {
+        it('throws when mutable change happens', () => {
           const state = stateFactory();
           const s = { user: { firstName: 'M', lastName: 'S' } };
           patchState(state, s);
@@ -82,6 +93,30 @@ describe('deepFreeze', () => {
             "Cannot assign to read only property 'firstName' of object"
           );
         });
+
+        describe('symbol', () => {
+          it('throws on a mutable change on property of a frozen symbol', () => {
+            const state = stateFactory();
+            const s = getState(state);
+
+            expect(() => {
+              s[SECRET].code = 'mutable change';
+            }).toThrowError(
+              "Cannot assign to read only property 'code' of object"
+            );
+          });
+
+          it('throws on a mutable change on nested symbol', () => {
+            const state = stateFactory();
+            const s = getState(state);
+
+            expect(() => {
+              s.nestedSymbol[SECRET] = 'mutable change';
+            }).toThrowError(
+              "Cannot assign to read only property 'Symbol(secret)' of object"
+            );
+          });
+        });
       });
     });
   }

modules/signals/spec/signal-store.spec.ts

@@ -1,4 +1,10 @@
-import { inject, InjectionToken, isSignal, signal } from '@angular/core';
+import {
+  computed,
+  inject,
+  InjectionToken,
+  isSignal,
+  signal,
+} from '@angular/core';
 import { TestBed } from '@angular/core/testing';
 import {
   patchState,
@@ -145,6 +151,14 @@ describe('signalStore', () => {
 
       expect(store.foo()).toBe('foo');
     });
+
+    it('can have symbols as keys as well', () => {
+      const SECRET = Symbol('SECRET');
+      const Store = signalStore(withState({ [SECRET]: 'bar' }));
+      const store = new Store();
+
+      expect(store[SECRET]()).toBe('bar');
+    });
   });
 
   describe('withProps', () => {
@@ -183,6 +197,50 @@ describe('signalStore', () => {
 
       expect(store.foo).toBe('bar');
     });
+
+    it('allows symbols as props', () => {
+      const SECRET = Symbol('SECRET');
+
+      const Store = signalStore(withProps(() => ({ [SECRET]: 'secret' })));
+      const store = TestBed.configureTestingModule({
+        providers: [Store],
+      }).inject(Store);
+
+      expect(store[SECRET]).toBe('secret');
+    });
+
+    it('allows numbers as props', () => {
+      const Store = signalStore(withProps(() => ({ 1: 'Number One' })));
+      const store = TestBed.configureTestingModule({
+        providers: [Store],
+      }).inject(Store);
+
+      expect(store[1]).toBe('Number One');
+    });
+
+    it('passes on a symbol to the features', () => {
+      const SECRET = Symbol('SECRET');
+      const SecretStore = signalStore(
+        { providedIn: 'root' },
+        withProps(() => ({
+          [SECRET]: 'not your business',
+        })),
+        withMethods((store) => ({
+          reveil() {
+            return store[SECRET];
+          },
+        })),
+        withComputed((state) => ({
+          secret: computed(() => state[SECRET]),
+        }))
+      );
+
+      const secretStore = TestBed.inject(SecretStore);
+
+      expect(secretStore.reveil()).toBe('not your business');
+      expect(secretStore.secret()).toBe('not your business');
+      expect(secretStore[SECRET]).toBe('not your business');
+    });
   });
 
   describe('withComputed', () => {
@@ -221,6 +279,26 @@ describe('signalStore', () => {
 
       expect(store.bar()).toBe('bar');
     });
+
+    it('can also expose a symbol', () => {
+      const SECRET = Symbol('SECRET');
+      const SecretStore = signalStore(
+        { providedIn: 'root' },
+        withComputed(() => ({
+          [SECRET]: computed(() => 'secret'),
+        })),
+        withMethods((store) => ({
+          reveil() {
+            return store[SECRET];
+          },
+        }))
+      );
+
+      const secretStore = TestBed.inject(SecretStore);
+      const secretSignal = secretStore.reveil();
+
+      expect(secretSignal()).toBe('secret');
+    });
   });
 
   describe('withMethods', () => {
@@ -263,6 +341,19 @@ describe('signalStore', () => {
 
       expect(store.baz()).toBe('baz');
     });
+
+    it('can also expose a symbol', () => {
+      const SECRET = Symbol('SECRET');
+      const SecretStore = signalStore(
+        { providedIn: 'root' },
+        withMethods(() => ({
+          [SECRET]: () => 'my secret',
+        }))
+      );
+      const secretStore = TestBed.inject(SecretStore);
+
+      expect(secretStore[SECRET]()).toBe('my secret');
+    });
   });
 
   describe('withHooks', () => {

modules/signals/spec/state-source.spec.ts

@@ -18,6 +18,8 @@ import {
 import { STATE_SOURCE } from '../src/state-source';
 import { createLocalService } from './helpers';
 
+const SECRET = Symbol('SECRET');
+
 describe('StateSource', () => {
   const initialState = {
     user: {
@@ -27,6 +29,7 @@ describe('StateSource', () => {
     foo: 'bar',
     numbers: [1, 2, 3],
     ngrx: 'signals',
+    [SECRET]: 'secret',
   };
 
   describe('patchState', () => {
@@ -78,6 +81,13 @@ describe('StateSource', () => {
           });
         });
 
+        it('patches property with symbol keys', () => {
+          const state = stateFactory();
+
+          patchState(state, { [SECRET]: 'another secret' });
+          expect(state[SECRET]()).toBe('another secret');
+        });
+
         it('patches state via sequence of partial state objects and updater functions', () => {
           const state = stateFactory();
 

modules/signals/spec/with-methods.spec.ts

@@ -19,14 +19,18 @@ describe('withMethods', () => {
   });
 
   it('logs warning if previously defined signal store members have the same name', () => {
+    const STATE_SECRET = Symbol('state_secret');
+    const COMPUTED_SECRET = Symbol('computed_secret');
     const initialStore = [
       withState({
         p1: 'p1',
         p2: false,
+        [STATE_SECRET]: 1,
       }),
       withComputed(() => ({
         s1: signal(true).asReadonly(),
         s2: signal({ s: 2 }).asReadonly(),
+        [COMPUTED_SECRET]: signal(1).asReadonly(),
       })),
       withMethods(() => ({
         m1() {},
@@ -43,12 +47,14 @@ describe('withMethods', () => {
       s1: () => 100,
       m2,
       m3: () => 'm3',
+      [STATE_SECRET]() {},
+      [COMPUTED_SECRET]() {},
     }))(initialStore);
 
     expect(console.warn).toHaveBeenCalledWith(
       '@ngrx/signals: SignalStore members cannot be overridden.',
       'Trying to override:',
-      'p2, s1, m2'
+      'p2, s1, m2, Symbol(state_secret), Symbol(computed_secret)'
     );
   });
 });

modules/signals/spec/with-props.spec.ts

@@ -1,8 +1,7 @@
 import { signal } from '@angular/core';
 import { of } from 'rxjs';
-import { signalStore, withMethods, withProps, withState } from '../src';
+import { withMethods, withProps, withState } from '../src';
 import { getInitialInnerStore } from '../src/signal-store';
-import { TestBed } from '@angular/core/testing';
 
 describe('withProps', () => {
   it('adds properties to the store immutably', () => {
@@ -48,24 +47,4 @@ describe('withProps', () => {
       's1, p2, m1'
     );
   });
-
-  it('allows symbols as props', () => {
-    const SECRET = Symbol('SECRET');
-
-    const Store = signalStore(withProps(() => ({ [SECRET]: 'secret' })));
-    const store = TestBed.configureTestingModule({ providers: [Store] }).inject(
-      Store
-    );
-
-    expect(store[SECRET]).toBe('secret');
-  });
-
-  it('allows numbers as props', () => {
-    const Store = signalStore(withProps(() => ({ 1: 'Number One' })));
-    const store = TestBed.configureTestingModule({ providers: [Store] }).inject(
-      Store
-    );
-
-    expect(store[1]).toBe('Number One');
-  });
 });

modules/signals/src/deep-freeze.ts

@@ -1,13 +1,12 @@
 declare const ngDevMode: boolean;
 
-export function deepFreeze<T>(target: T): T {
+export function deepFreeze<T extends object>(target: T): T {
   Object.freeze(target);
 
   const targetIsFunction = typeof target === 'function';
 
-  Object.getOwnPropertyNames(target).forEach((prop) => {
-    // Ignore Ivy properties, ref: https://github.com/ngrx/platform/issues/2109#issuecomment-582689060
-    if (prop.startsWith('ɵ')) {
+  Reflect.ownKeys(target).forEach((prop) => {
+    if (String(prop).startsWith('ɵ')) {
       return;
     }
 

modules/signals/src/signal-store-assertions.ts

@@ -4,7 +4,7 @@ declare const ngDevMode: unknown;
 
 export function assertUniqueStoreMembers(
   store: InnerSignalStore,
-  newMemberKeys: string[]
+  newMemberKeys: (string | symbol)[]
 ): void {
   if (!ngDevMode) {
     return;
@@ -15,15 +15,15 @@ export function assertUniqueStoreMembers(
     ...store.props,
     ...store.methods,
   };
-  const overriddenKeys = Object.keys(storeMembers).filter((memberKey) =>
+  const overriddenKeys = Reflect.ownKeys(storeMembers).filter((memberKey) =>
     newMemberKeys.includes(memberKey)
   );
 
   if (overriddenKeys.length > 0) {
     console.warn(
       '@ngrx/signals: SignalStore members cannot be overridden.',
       'Trying to override:',
-      overriddenKeys.join(', ')
+      overriddenKeys.map((key) => String(key)).join(', ')
     );
   }
 }

modules/signals/src/with-methods.ts

@@ -30,7 +30,7 @@ export function withMethods<
       ...store.props,
       ...store.methods,
     });
-    assertUniqueStoreMembers(store, Object.keys(methods));
+    assertUniqueStoreMembers(store, Reflect.ownKeys(methods));
 
     return {
       ...store,

modules/signals/src/with-state.ts

@@ -32,7 +32,7 @@ export function withState<State extends object>(
   return (store) => {
     const state =
       typeof stateOrFactory === 'function' ? stateOrFactory() : stateOrFactory;
-    const stateKeys = Object.keys(state);
+    const stateKeys = Reflect.ownKeys(state);
 
     assertUniqueStoreMembers(store, stateKeys);