init

src/stores/cart/useCartStore.ts

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+import { create } from 'zustand'
+import Taro from '@tarojs/taro'
+import {
+  addCartApi,
+  clearCartApi,
+  deleteCartItemApi,
+  getCartApi,
+  updateCartItemApi,
+} from '@/services/cart'
+import type { CartItem } from '@/types/cart'
+
+/** 存储 key */
+const STORAGE_KEY = 'cart_data'
+
+/** 持久化的购物车快照（服务端为准，此处仅作展示缓存） */
+interface StoredCart {
+  items: CartItem[]
+  totalCount: number
+  totalQuantity: string
+  totalAmount: string
+}
+
+/** 从本地存储恢复购物车快照 */
+function loadFromStorage(): StoredCart | null {
+  try {
+    const stored = Taro.getStorageSync(STORAGE_KEY)
+    if (stored && Array.isArray(stored.items)) {
+      return stored as StoredCart
+    }
+  } catch {
+    // noop
+  }
+  return null
+}
+
+interface CartState {
+  items: CartItem[]
+  /** 总项数 */
+  totalCount: number
+  /** 可购项总数量（服务端字符串金额/数量） */
+  totalQuantity: string
+  /** 可购项总金额（服务端重算） */
+  totalAmount: string
+  /** 是否已从服务端同步过（避免每次展示都闪烁 loading） */
+  loaded: boolean
+  loading: boolean
+  /** 拉取购物车（以服务端为准，金额一律服务端重算） */
+  fetchCart: () => Promise<void>
+  /** 加购 */
+  addItem: (productId: number, quantity: number) => Promise<void>
+  /** 修改数量 */
+  updateQuantity: (id: number, quantity: number) => Promise<void>
+  /** 删除单项 */
+  removeItem: (id: number) => Promise<void>
+  /** 清空购物车 */
+  clearCart: () => Promise<void>
+  /** 下单成功后本地清空（不请求接口） */
+  clearLocal: () => void
+}
+
+/** 空的购物车快照 */
+const EMPTY_SNAPSHOT = {
+  items: [] as CartItem[],
+  totalCount: 0,
+  totalQuantity: '0.00',
+  totalAmount: '0.00',
+}
+
+const useCartStore = create<CartState>((set, get) => {
+  const cached = loadFromStorage()
+
+  /** 持久化购物车快照 */
+  const persist = (
+    snapshot: Pick<CartState, 'items' | 'totalCount' | 'totalQuantity' | 'totalAmount'>,
+  ) => {
+    try {
+      Taro.setStorageSync(STORAGE_KEY, snapshot)
+    } catch {
+      // storage 写入失败不阻塞
+    }
+  }
+
+  return {
+    ...EMPTY_SNAPSHOT,
+    items: cached?.items ?? [],
+    totalCount: cached?.totalCount ?? 0,
+    totalQuantity: cached?.totalQuantity ?? '0.00',
+    totalAmount: cached?.totalAmount ?? '0.00',
+    loaded: false,
+    loading: false,
+
+    /** 拉取购物车（服务端为准） */
+    fetchCart: async () => {
+      if (get().loading) return
+      set({ loading: true })
+      try {
+        const res = await getCartApi()
+        const { items, total_count, total_quantity, total_amount } = res.data
+        const next = {
+          items,
+          totalCount: total_count,
+          totalQuantity: total_quantity,
+          totalAmount: total_amount,
+        }
+        set({ ...next, loaded: true })
+        persist(next)
+      } finally {
+        set({ loading: false })
+      }
+    },
+
+    /** 加购：服务端校验上架与等级价，成功后重新同步 */
+    addItem: async (productId, quantity) => {
+      await addCartApi({ product_id: productId, quantity })
+      await get().fetchCart()
+    },
+
+    /** 修改数量 */
+    updateQuantity: async (id, quantity) => {
+      await updateCartItemApi(id, quantity)
+      await get().fetchCart()
+    },
+
+    /** 删除单项 */
+    removeItem: async (id) => {
+      await deleteCartItemApi(id)
+      await get().fetchCart()
+    },
+
+    /** 清空购物车 */
+    clearCart: async () => {
+      await clearCartApi()
+      set({ ...EMPTY_SNAPSHOT, loaded: true })
+      persist(EMPTY_SNAPSHOT)
+    },
+
+    /** 下单成功后本地清空 */
+    clearLocal: () => {
+      set(EMPTY_SNAPSHOT)
+      persist(EMPTY_SNAPSHOT)
+    },
+  }
+})
+
+export default useCartStore