提问

问题描述：

老师，这里报错提示传入的shopId是常量？

相关截图：

相关代码：

​import { createStore } from "vuex";

export default createStore({
  state: {
    cartList: {},
  },
  mutations: {
    ChangeCartItemInfo(state, payload) {
      const { shopId, productId, productInfo, num } = payload;
      let shopInfo = state.cartList[shopId];
      if (!shopInfo) {
        shopId = {};
      }
      let product = shopInfo[productId];
      if (!productInfo) {
        product = productInfo;
        product.count = 0;
      }
      product.count = product.count + num;
      if (product.count < 0) {
        product.count = 0;
      } else if (product.count > 99) {
        product.count = 99;
      }
      shopInfo[productId] = product;
      state.cartList[shopId] = shopInfo;
    },
  },
  actions: {},
  modules: {},
});