feat: add InternalStore utility class

npm/ng-packs/packages/core/src/lib/tests/internal-store.spec.ts

@@ -0,0 +1,108 @@
+import clone from 'just-clone';
+import { take } from 'rxjs/operators';
+import { DeepPartial } from '../models';
+import { InternalStore } from '../utils';
+
+const mockInitialState = {
+  foo: {
+    bar: {
+      baz: [() => {}],
+      qux: null as Promise<any>,
+    },
+    n: 0,
+  },
+  x: '',
+  a: false,
+};
+
+type MockState = typeof mockInitialState;
+
+const patch1: DeepPartial<MockState> = { foo: { bar: { baz: [() => {}] } } };
+const expected1: MockState = clone(mockInitialState);
+expected1.foo.bar.baz = patch1.foo.bar.baz;
+
+const patch2: DeepPartial<MockState> = { foo: { bar: { qux: Promise.resolve() } } };
+const expected2: MockState = clone(mockInitialState);
+expected2.foo.bar.qux = patch2.foo.bar.qux;
+
+const patch3: DeepPartial<MockState> = { foo: { n: 1 } };
+const expected3: MockState = clone(mockInitialState);
+expected3.foo.n = patch3.foo.n;
+
+const patch4: DeepPartial<MockState> = { x: 'X' };
+const expected4: MockState = clone(mockInitialState);
+expected4.x = patch4.x;
+
+const patch5: DeepPartial<MockState> = { a: true };
+const expected5: MockState = clone(mockInitialState);
+expected5.a = patch5.a;
+
+describe('Internal Store', () => {
+  describe('sliceState', () => {
+    test.each`
+      selector                                   | expected
+      ${(state: MockState) => state.a}           | ${mockInitialState.a}
+      ${(state: MockState) => state.x}           | ${mockInitialState.x}
+      ${(state: MockState) => state.foo.n}       | ${mockInitialState.foo.n}
+      ${(state: MockState) => state.foo.bar}     | ${mockInitialState.foo.bar}
+      ${(state: MockState) => state.foo.bar.baz} | ${mockInitialState.foo.bar.baz}
+      ${(state: MockState) => state.foo.bar.qux} | ${mockInitialState.foo.bar.qux}
+    `(
+      'should return observable $expected when selector is $selector',
+      async ({ selector, expected }) => {
+        const store = new InternalStore(mockInitialState);
+
+        const value = await store
+          .sliceState(selector)
+          .pipe(take(1))
+          .toPromise();
+
+        expect(value).toEqual(expected);
+      },
+    );
+  });
+
+  describe('patchState', () => {
+    test.each`
+      patch     | expected
+      ${patch1} | ${expected1}
+      ${patch2} | ${expected2}
+      ${patch3} | ${expected3}
+      ${patch4} | ${expected4}
+      ${patch5} | ${expected5}
+    `('should set state as $expected when patch is $patch', ({ patch, expected }) => {
+      const store = new InternalStore(mockInitialState);
+
+      store.patch(patch);
+
+      expect(store.state).toEqual(expected);
+    });
+  });
+
+  describe('sliceUpdate', () => {
+    it('should return slice of update$ based on selector', done => {
+      const store = new InternalStore(mockInitialState);
+
+      const onQux$ = store.sliceUpdate(state => state.foo.bar.qux);
+
+      onQux$.pipe(take(1)).subscribe(value => {
+        expect(value).toEqual(patch2.foo.bar.qux);
+        done();
+      });
+
+      store.patch(patch1);
+      store.patch(patch2);
+    });
+  });
+
+  describe('reset', () => {
+    it('should reset state to initialState', () => {
+      const store = new InternalStore(mockInitialState);
+
+      store.patch(patch1);
+      store.reset();
+
+      expect(store.state).toEqual(mockInitialState);
+    });
+  });
+});

npm/ng-packs/packages/core/src/lib/utils/index.ts

@@ -6,6 +6,7 @@ export * from './factory-utils';
 export * from './form-utils';
 export * from './generator-utils';
 export * from './initial-utils';
+export * from './internal-store-utils';
 export * from './lazy-load-utils';
 export * from './localization-utils';
 export * from './multi-tenancy-utils';

npm/ng-packs/packages/core/src/lib/utils/internal-store-utils.ts

@@ -0,0 +1,36 @@
+import compare from 'just-compare';
+import { BehaviorSubject, Subject } from 'rxjs';
+import { distinctUntilChanged, filter, map } from 'rxjs/operators';
+import { DeepPartial } from '../models';
+import { deepMerge } from './object-utils';
+
+export class InternalStore<State> {
+  private state$ = new BehaviorSubject<State>(this.initialState);
+
+  private update$ = new Subject<DeepPartial<State>>();
+
+  get state() {
+    return this.state$.value;
+  }
+
+  sliceState = <Slice>(
+    selector: (state: State) => Slice,
+    compareFn: (s1: Slice, s2: Slice) => boolean = compare,
+  ) => this.state$.pipe(map(selector), distinctUntilChanged(compareFn));
+
+  sliceUpdate = <Slice>(
+    selector: (state: DeepPartial<State>) => Slice,
+    filterFn = (x: Slice) => x !== undefined,
+  ) => this.update$.pipe(map(selector), filter(filterFn));
+
+  constructor(private initialState: State) {}
+
+  patch(state: DeepPartial<State>) {
+    this.state$.next(deepMerge(this.state, state));
+    this.update$.next(state);
+  }
+
+  reset() {
+    this.patch(this.initialState);
+  }
+}