fix(signals): define SignalStore members as readonly

modules/signals/spec/readonly-issue-demo.spec.ts

@@ -0,0 +1,37 @@
+import { expecter } from 'ts-snippet';
+import { compilerOptions } from './types/helpers';
+
+describe('signalStore readonly members', () => {
+  const expectSnippet = expecter(
+    (code) => `
+      import { computed, signal, Signal } from '@angular/core';
+      import { patchState, signalStore, withComputed, withMethods, withState } from '@ngrx/signals';
+
+      const UserStore = signalStore(
+        withState<{ name: string; age: number }>({ name: 'Alice', age: 30 }),
+        withComputed((store) => ({
+          greeting: computed(() => 'Hi, ' + store.name()),
+        })),
+        withMethods((store) => ({
+          setName(name: string) { patchState(store, { name }); },
+        }))
+      );
+
+      const store = new UserStore();
+      ${code}
+    `,
+    compilerOptions()
+  );
+
+  it('prevents reassigning state signals', () => {
+    expectSnippet(`store.name = signal('x') as unknown as Signal<string>;`).toFail(/read-only/);
+  });
+
+  it('prevents reassigning computed signals', () => {
+    expectSnippet(`store.greeting = signal('x') as unknown as Signal<string>;`).toFail(/read-only/);
+  });
+
+  it('prevents reassigning methods', () => {
+    expectSnippet(`store.setName = (n: string) => {};`).toFail(/read-only/);
+  });
+});

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

@@ -33,7 +33,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'Store',
-      'Type<{ foo: Signal<string>; bar: Signal<number[]>; } & StateSource<{ foo: string; bar: number[]; }>>'
+      'Type<{ readonly foo: Signal<string>; readonly bar: Signal<number[]>; } & StateSource<{ foo: string; bar: number[]; }>>'
     );
   });
 
@@ -62,7 +62,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store',
-      '{ user: DeepSignal<{ age: number; details: { first: string; flags: boolean[]; }; }>; } & StateSource<{ user: { age: number; details: { first: string; flags: boolean[]; }; }; }>'
+      '{ readonly user: DeepSignal<{ age: number; details: { first: string; flags: boolean[]; }; }>; } & StateSource<{ user: { age: number; details: { first: string; flags: boolean[]; }; }; }>'
     );
     result.toInfer(
       'user',
@@ -240,7 +240,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store',
-      '{ foo: Signal<number | { s: string; }>; bar: DeepSignal<{ baz: { b: boolean; } | null; }>; x: DeepSignal<{ y: { z: number | undefined; }; }>; } & StateSource<{ foo: number | { ...; }; bar: { ...; }; x: { ...; }; }>'
+      '{ readonly foo: Signal<number | { s: string; }>; readonly bar: DeepSignal<{ baz: { b: boolean; } | null; }>; readonly x: DeepSignal<{ y: { z: number | undefined; }; }>; } & StateSource<...>'
     );
     result.toInfer('foo', 'Signal<number | { s: string; }>');
     result.toInfer('bar', 'DeepSignal<{ baz: { b: boolean; } | null; }>');
@@ -264,7 +264,7 @@ describe('signalStore', () => {
     const result1 = expectSnippet(snippet1);
     result1.toInfer(
       'Store',
-      'Type<{ name: DeepSignal<{ x: { y: string; }; }>; arguments: Signal<number[]>; call: Signal<boolean>; } & StateSource<{ name: { x: { y: string; }; }; arguments: number[]; call: boolean; }>>'
+      'Type<{ readonly name: DeepSignal<{ x: { y: string; }; }>; readonly arguments: Signal<number[]>; readonly call: Signal<boolean>; } & StateSource<{ name: { x: { y: string; }; }; arguments: number[]; call: boolean; }>>'
     );
 
     const snippet2 = `
@@ -280,7 +280,7 @@ describe('signalStore', () => {
     const result2 = expectSnippet(snippet2);
     result2.toInfer(
       'Store',
-      'Type<{ apply: Signal<string>; bind: DeepSignal<{ foo: string; }>; prototype: Signal<string[]>; } & StateSource<{ apply: string; bind: { foo: string; }; prototype: string[]; }>>'
+      'Type<{ readonly apply: Signal<string>; readonly bind: DeepSignal<{ foo: string; }>; readonly prototype: Signal<string[]>; } & StateSource<{ apply: string; bind: { foo: string; }; prototype: string[]; }>>'
     );
 
     const snippet3 = `
@@ -295,7 +295,7 @@ describe('signalStore', () => {
     const result3 = expectSnippet(snippet3);
     result3.toInfer(
       'Store',
-      'Type<{ length: Signal<number>; caller: Signal<undefined>; } & StateSource<{ length: number; caller: undefined; }>>'
+      'Type<{ readonly length: Signal<number>; readonly caller: Signal<undefined>; } & StateSource<{ length: number; caller: undefined; }>>'
     );
   });
 
@@ -343,7 +343,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store',
-      '{ bar: DeepSignal<{ baz?: number | undefined; }>; x: DeepSignal<{ y?: { z: boolean; } | undefined; }>; } & StateSource<{ bar: { baz?: number | undefined; }; x: { y?: { z: boolean; } | undefined; }; }>'
+      '{ readonly bar: DeepSignal<{ baz?: number | undefined; }>; readonly x: DeepSignal<{ y?: { z: boolean; } | undefined; }>; } & StateSource<{ bar: { baz?: number | undefined; }; x: { ...; }; }>'
     );
     result.toInfer('bar', 'DeepSignal<{ baz?: number | undefined; }>');
     result.toInfer('baz', 'Signal<number | undefined> | undefined');
@@ -433,12 +433,12 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store1',
-      '{ count: Signal<number>; } & StateSource<{ count: number; }>'
+      '{ readonly count: Signal<number>; } & StateSource<{ count: number; }>'
     );
     result.toInfer('state1', '{ count: number; }');
     result.toInfer(
       'store2',
-      '{ count: Signal<number>; } & StateSource<{ count: number; }>'
+      '{ readonly count: Signal<number>; } & StateSource<{ count: number; }>'
     );
     result.toInfer('state2', '{ count: number; }');
 
@@ -474,12 +474,12 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store1',
-      '{ count: Signal<number>; } & StateSource<{ count: number; }>'
+      '{ readonly count: Signal<number>; } & StateSource<{ count: number; }>'
     );
     result.toInfer('state1', '{ count: number; }');
     result.toInfer(
       'store2',
-      '{ count: Signal<number>; } & StateSource<{ count: number; }>'
+      '{ readonly count: Signal<number>; } & StateSource<{ count: number; }>'
     );
     result.toInfer('state2', '{ count: number; }');
 
@@ -515,12 +515,12 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store1',
-      '{ count: Signal<number>; } & WritableStateSource<{ count: number; }>'
+      '{ readonly count: Signal<number>; } & WritableStateSource<{ count: number; }>'
     );
     result.toInfer('state1', '{ count: number; }');
     result.toInfer(
       'store2',
-      '{ count: Signal<number>; } & WritableStateSource<{ count: number; }>'
+      '{ readonly count: Signal<number>; } & WritableStateSource<{ count: number; }>'
     );
     result.toInfer('state2', '{ count: number; }');
 
@@ -680,7 +680,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store',
-      '{ ngrx: Signal<string>; x: DeepSignal<{ y: string; }>; signals: Signal<number[]>; mgmt: (arg: boolean) => number; } & StateSource<{ ngrx: string; x: { y: string; }; }>'
+      '{ readonly ngrx: Signal<string>; readonly x: DeepSignal<{ y: string; }>; readonly signals: Signal<number[]>; readonly mgmt: (arg: boolean) => number; } & StateSource<...>'
     );
   });
 
@@ -707,7 +707,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store',
-      '{ foo: Signal<number>; bar: Signal<string>; baz: (x: number) => void; } & StateSource<{ foo: number; }>'
+      '{ readonly foo: Signal<number>; readonly bar: Signal<string>; readonly baz: (x: number) => void; } & StateSource<{ foo: number; }>'
     );
   });
 
@@ -754,7 +754,7 @@ describe('signalStore', () => {
     const result = expectSnippet(snippet);
     result.toInfer(
       'store',
-      '{ count1: Signal<number>; doubleCount2: Signal<number>; increment1: () => void; } & StateSource<{ count1: number; }>'
+      '{ readonly count1: Signal<number>; readonly doubleCount2: Signal<number>; readonly increment1: () => void; } & StateSource<{ count1: number; }>'
     );
   });
 

modules/signals/src/signal-store.ts

@@ -15,10 +15,12 @@ type SignalStoreConfig = ProvidedInConfig & { protectedState?: boolean };
 
 type SignalStoreMembers<FeatureResult extends SignalStoreFeatureResult> =
   Prettify<
-    OmitPrivate<
-      StateSignals<FeatureResult['state']> &
-        FeatureResult['props'] &
-        FeatureResult['methods']
+    Readonly<
+      OmitPrivate<
+        StateSignals<FeatureResult['state']> &
+          FeatureResult['props'] &
+          FeatureResult['methods']
+      >
     >
   >;
 

modules/signals/testing/spec/types/uprotected.types.spec.ts

@@ -28,7 +28,7 @@ describe('unprotected', () => {
 
     expectSnippet(snippet).toInfer(
       'unprotectedStore',
-      '{ count: Signal<number>; doubleCount: Signal<number>; [STATE_SOURCE]: { count: WritableSignal<number>; }; }'
+      '{ readonly count: Signal<number>; readonly doubleCount: Signal<number>; [STATE_SOURCE]: { count: WritableSignal<number>; }; }'
     );
   });
 
@@ -45,7 +45,7 @@ describe('unprotected', () => {
 
     expectSnippet(snippet).toInfer(
       'unprotectedStore',
-      '{ count: Signal<number>; [STATE_SOURCE]: { count: WritableSignal<number>; }; }'
+      '{ readonly count: Signal<number>; [STATE_SOURCE]: { count: WritableSignal<number>; }; }'
     );
   });
 }, 8_000);