feat(signals): add getState function (#4118)

Author: jits

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

@@ -0,0 +1,53 @@
+import { TestBed } from '@angular/core/testing';
+import {
+  getState,
+  patchState,
+  signalState,
+  signalStore,
+  withState,
+} from '../src';
+import { effect } from '@angular/core';
+
+describe('getState', () => {
+  const initialState = {
+    user: {
+      firstName: 'John',
+      lastName: 'Smith',
+    },
+    foo: 'bar',
+    numbers: [1, 2, 3],
+    ngrx: 'signals',
+  };
+
+  describe('with signalStore', () => {
+    it('returns the state object', () => {
+      const Store = signalStore(withState(initialState));
+      const store = new Store();
+
+      expect(getState(store)).toEqual(initialState);
+    });
+
+    it('executes in the reactive context', () => {
+      const Store = signalStore(withState(initialState));
+      const store = new Store();
+
+      let executionCount = 0;
+
+      TestBed.runInInjectionContext(() => {
+        effect(() => {
+          getState(store);
+          executionCount++;
+        });
+      });
+
+      TestBed.flushEffects();
+      expect(executionCount).toBe(1);
+
+      patchState(store, { foo: 'baz' });
+
+      TestBed.flushEffects();
+      expect(executionCount).toBe(2);
+      expect(getState(store)).toEqual({ ...initialState, foo: 'baz' });
+    });
+  });
+});

modules/signals/src/get-state.ts

@@ -0,0 +1,7 @@
+import { STATE_SIGNAL, SignalStateMeta } from './signal-state';
+
+export function getState<State extends Record<string, unknown>>(
+  signalState: SignalStateMeta<State>
+): State {
+  return signalState[STATE_SIGNAL]();
+}

modules/signals/src/index.ts

@@ -1,3 +1,4 @@
+export { getState } from './get-state';
 export { PartialStateUpdater, patchState } from './patch-state';
 export { signalState } from './signal-state';
 export { signalStore } from './signal-store';