feat(cart): add cart retrieval action support (#2557)

libs/cart/state/src/cart-retrieval/get-response.spec.ts

@@ -0,0 +1,77 @@
+import { TestBed } from '@angular/core/testing';
+import { Action } from '@ngrx/store';
+
+import { DaffCart } from '@daffodil/cart';
+import {
+  DaffCartRetrievalAction,
+  DaffCartRetrievalActionInjection,
+} from '@daffodil/cart/state';
+import { DaffCartFactory } from '@daffodil/cart/testing';
+
+import { daffCartRetrievalGetResponse } from './get-response';
+
+class DirectAction implements DaffCartRetrievalAction {
+  type = 'direct';
+  constructor(public payload: DaffCart) {}
+}
+
+class TransformAction implements Action {
+  type = 'transform';
+  constructor(public response: DaffCart) {}
+}
+
+describe('@daffodil/cart/state | daffCartRetrievalGetResponse', () => {
+  let result: Partial<DaffCart> | null;
+  let actions: DaffCartRetrievalActionInjection[];
+  let cartFactory: DaffCartFactory;
+  let mockCart: DaffCart;
+
+  beforeEach(() => {
+    cartFactory = TestBed.inject(DaffCartFactory);
+
+    mockCart = cartFactory.create();
+    actions = [
+      { type: 'direct' },
+      { type: 'transform', transform: <any>((action: TransformAction) => action.response) },
+    ];
+  });
+
+  describe('when the action is not a recognized retrieval action', () => {
+    beforeEach(() => {
+      result = daffCartRetrievalGetResponse(
+        { type: 'unknown' },
+        actions,
+      );
+    });
+
+    it('should return null', () => {
+      expect(result).toBeNull();
+    });
+  });
+
+  describe('when the action is direct', () => {
+    beforeEach(() => {
+      result = daffCartRetrievalGetResponse(
+        new DirectAction(mockCart),
+        actions,
+      );
+    });
+
+    it('should return the cart', () => {
+      expect(result).toEqual(mockCart);
+    });
+  });
+
+  describe('when the action is transform', () => {
+    beforeEach(() => {
+      result = daffCartRetrievalGetResponse(
+        new TransformAction(mockCart),
+        actions,
+      );
+    });
+
+    it('should return the cart', () => {
+      expect(result).toEqual(mockCart);
+    });
+  });
+});

libs/cart/state/src/cart-retrieval/get-response.ts

@@ -0,0 +1,22 @@
+import { Action } from '@ngrx/store';
+
+import { DaffCart } from '@daffodil/cart';
+
+import {
+  DaffCartRetrievalAction,
+  DaffCartRetrievalActionInjection,
+  DaffCartRetrievalActionTransformedInjection,
+} from './type';
+
+/**
+ * Gets the cart from the passed action if it is a recognized retrieval action and applying the transformation if needed.
+ */
+export function daffCartRetrievalGetResponse<T extends DaffCart = DaffCart>(action: Action, retrievalActions: DaffCartRetrievalActionInjection[]): Partial<T> | null {
+  const actionInjection = retrievalActions.find(({ type }) => type === action.type);
+
+  if (actionInjection) {
+    return (<DaffCartRetrievalActionTransformedInjection>actionInjection).transform?.<T>(action) || (<DaffCartRetrievalAction<T>>action).payload;
+  }
+
+  return null;
+}

libs/cart/state/src/cart-retrieval/public_api.ts

@@ -0,0 +1,3 @@
+export * from './token';
+export * from './type';
+export * from './get-response';

libs/cart/state/src/cart-retrieval/token.ts

@@ -0,0 +1,21 @@
+import {
+  InjectionToken,
+  ValueProvider,
+} from '@angular/core';
+
+import { DaffCartRetrievalActionInjection } from './type';
+
+/**
+ * A token to hold {@link DaffCartRetrievalActionInjection}s.
+ */
+export const DAFF_CART_RETRIEVAL_ACTIONS = new InjectionToken<DaffCartRetrievalActionInjection[]>('DAFF_CART_RETRIEVAL_ACTIONS', { factory: () => []});
+
+/**
+ * A provider function for {@link DAFF_CART_RETRIEVAL_ACTIONS}.
+ */
+export const daffCartProvideRetrievalActions = (...actions: DaffCartRetrievalActionInjection[]): ValueProvider[] =>
+  actions.map((action) => ({
+    provide: DAFF_CART_RETRIEVAL_ACTIONS,
+    useValue: action,
+    multi: true,
+  }));

libs/cart/state/src/cart-retrieval/type.ts

@@ -0,0 +1,46 @@
+import { Action } from '@ngrx/store';
+
+import { DaffCart } from '@daffodil/cart';
+
+/**
+ * Represents an action that loads a portion of the cart.
+ */
+export interface DaffCartRetrievalAction<T extends DaffCart = DaffCart> extends Action {
+  readonly payload: Partial<T>;
+}
+
+/**
+ * Represents an injection of a retrieval action that implements the {@link DaffCartRetrievalAction} interface
+ * and therefore does not need transformation.
+ * If the injected action needs transformation, use {@link DaffCartRetrievalActionTransformedInjection}
+ */
+export interface DaffCartRetrievalActionDirectInjection<T extends DaffCartRetrievalAction = DaffCartRetrievalAction> {
+  /**
+   * The action type.
+   */
+  type: T['type'];
+}
+
+/**
+ * Represents an injection of a retrieval action that doesn't implement the {@link DaffCartRetrievalAction} interface.
+ * Contains a way to get the cart from the action.
+ */
+export interface DaffCartRetrievalActionTransformedInjection<T extends Action = Action> {
+  /**
+   * The action type.
+   */
+  type: T['type'];
+
+  /**
+   * A function that gets the retrieved cart from the action.
+   */
+  transform: <TCart extends DaffCart = DaffCart>(action: T) => Partial<TCart>;
+}
+
+/**
+ * Represents an injection of a cart retrieval action.
+ * These actions are typically dispatched when an operation that mutates or loads the cart completes.
+ * Actions provided to {@link DAFF_CART_RETRIEVAL_ACTIONS} are natively understood by Daffodil reducers and will automatically
+ * populate the appropriate pieces of state when they are dispatched.
+ */
+export type DaffCartRetrievalActionInjection = DaffCartRetrievalActionDirectInjection | DaffCartRetrievalActionTransformedInjection;

libs/cart/state/src/public_api.ts

@@ -1,4 +1,5 @@
 export * from './actions/public_api';
+export * from './cart-retrieval/public_api';
 export * from './selectors/public_api';
 export * from './reducers/public_api';
 export * from './models/public_api';