feat(Store): createSelector with only a props selector

modules/store/spec/integration.spec.ts

@@ -177,6 +177,38 @@ describe('ngRx Integration spec', () => {
  });
 
  it('should use props to get a todo', () => {
+ const getTodosById = createSelector(
+ (state: TodoAppSchema, id: number) => {
+ return state.todos.find(p => p.id === id);
+ }
+ );
+
+ let testCase = 1;
+ const todo$ = store.pipe(select(getTodosById, 2));
+ todo$.subscribe(todo => {
+ if (testCase === 1) {
+ expect(todo).toEqual(undefined);
+ } else if (testCase === 2) {
+ expect(todo).toEqual({
+ id: 2,
+ text: 'second todo',
+ completed: false,
+ });
+ } else if (testCase === 3) {
+ expect(todo).toEqual({ id: 2, text: 'second todo', completed: true });
+ }
+ testCase++;
+ });
+
+ store.dispatch({ type: ADD_TODO, payload: { text: 'first todo' } });
+ store.dispatch({ type: ADD_TODO, payload: { text: 'second todo' } });
+ store.dispatch({
+ type: COMPLETE_TODO,
+ payload: { id: 2 },
+ });
+ });
+
+ it('should use the selector and props to get a todo', () => {
  const getTodosState = createFeatureSelector<TodoAppSchema, Todo[]>(
  'todos'
  );

modules/store/spec/selector.spec.ts

@@ -224,6 +224,51 @@ describe('Selectors', () => {
  });
  });
 
+ describe('createSelector with only a props selector', () => {
+ it('should deliver the state and the props to the projection function', () => {
+ const projectFn = jasmine.createSpy('projectionFn');
+ const state = { counter: {} };
+ const props = { value: 47 };
+ const selector = createSelector(projectFn)(state, props);
+ expect(projectFn).toHaveBeenCalledWith(state, props);
+ });
+
+ it('should be possible to use a projector fn', () => {
+ const projectFn = jasmine.createSpy('projectionFn');
+ const selector = createSelector(projectFn);
+ selector.projector('foo', 'bar');
+ expect(projectFn).toHaveBeenCalledWith('foo', 'bar');
+ });
+
+ it('should call the projector function when the state changes', () => {
+ const projectFn = jasmine.createSpy('projectionFn');
+ const selector = createSelector(projectFn);
+
+ const firstState = { first: 'state' };
+ const secondState = { second: 'state' };
+ const props = { foo: 'props' };
+ selector(firstState, props);
+ selector(firstState, props);
+ selector(secondState, props);
+ expect(projectFn).toHaveBeenCalledTimes(2);
+ });
+
+ it('should allow you to release memoized arguments', () => {
+ const state = { first: 'state' };
+ const props = { first: 'props' };
+ const projectFn = jasmine.createSpy('projectionFn');
+ const selector = createSelector(projectFn);
+
+ selector(state, props);
+ selector(state, props);
+ selector.release();
+ selector(state, props);
+ selector(state, props);
+
+ expect(projectFn).toHaveBeenCalledTimes(2);
+ });
+ });
+
  describe('createSelector with arrays', () => {
  it('should deliver the value of selectors to the projection function', () => {
  const projectFn = jasmine.createSpy('projectionFn');

modules/store/src/selector.ts

@@ -435,6 +435,10 @@ export function createSelector<
  ) => Result
 ): MemoizedSelectorWithProps<State, Props, Result>;
 
+export function createSelector<State, Props, Result>(
+ projector: SelectorWithProps<State, Props, Result>
+): MemoizedSelectorWithProps<State, Props, Result>;
+
 export function createSelector(
  ...input: any[]
 ): Selector<any, any> | SelectorWithProps<any, any, any> {
@@ -501,6 +505,12 @@ export function createSelectorFactory(
  });
 
  const memoizedState = defaultMemoize(function(state: any, props: any) {
+ // createSelector works directly on state
+ // e.g. createSelector((state, props) => ...)
+ if (selectors.length === 0) {
+ return projector.apply(null, [state, props]);
+ }
+
  return options.stateFn.apply(null, [
  state,
  selectors,