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如何获取 SAP Commerce Cloud Spartacus UI 购物车 Cart 的加载状态

2021-09-15 14:59:56 作者：互联网

在 Storefront AppModule 构造函数里注入 ActiveCartService：

private cartService: ActiveCartService,

调用其 API：

const loading$ = this.cartService.getLoading();
    
    loading$.subscribe((data) => console.log('Jerry cart loading? ', data));

打印出的日志：

active-cart.service.d.ts 里，仅仅包含方法的参数定义：

如果要查看其实现代码，还是得去 fesm2015 的 Spartacus-core.js 文件里查看：

getLoading(): Observable<boolean> {
    return this.cartSelector$.pipe(
      map((cartEntity) => cartEntity.loading),
      distinctUntilChanged()
    );
  }

查看 this.cartSelector$ 的实现：

// Stream with active cart entity
  protected cartSelector$ = this.activeCartId$.pipe(
    switchMap((cartId) => this.multiCartService.getCartEntity(cartId))
  );

cartSelector$ 的赋值逻辑：从 activeCartId$ 里取出 cartId，调用 multiCartService 读取。

MultiCartService 也只是从 store 里通过selector 去读取。

ActiveCartId$ 的赋值逻辑：

// This stream is used for referencing carts in API calls.
  protected activeCartId$ = this.userIdService.getUserId().pipe(
    // We want to wait with initialization of cartId until we have userId initialized
    // We have take(1) to not trigger this stream, when userId changes.
    take(1),
    switchMapTo(this.store),
    select(MultiCartSelectors.getActiveCartId),
    // We also wait until we initialize cart from localStorage. Before that happens cartId in store === null
    filter((cartId) => cartId !== activeCartInitialState),
    map((cartId) => {
      if (cartId === '') {
        // We fallback to current when we don't have particular cart id -> cartId === '', because that's how you reference latest user cart.
        return OCC_CART_ID_CURRENT;
      }
      return cartId;
    })
  );

在这个文件处加上一行打印语句：