单击按钮时无法将商品添加到购物车

Question

When i click on the cart symbol, it changes its value to be in cart but actually my product is not rendered on the cart component, is there something wrong or missing in my code, please help me to fix it! Thank you so much!

Context.js:

class ProductProvider extends React.Component {
  state = {
    products: storeProducts,
    detailProduct: detailProduct,
    cart: [],
    modalOpen: false,
    modalProduct: detailProduct
  };

  getItem = (id) => {
    const product = this.state.products.find((item) => item.id === id);
    return product;
  };

  addToCart = (id) => {
    console.log("add to cart");
    let tempProducts = [...this.state.products];
    const index = tempProducts.indexOf(this.getItem(id));
    const product = tempProducts[index];
    product.inCart = true;
    product.count = 1;
    const price = product.price;
    product.total = price;

    this.setState(() => {
      return (
        { products: tempProducts, cart: [...this.state.cart, product] },
        () => console.log(this.state)
      );
    });
  };

  openModal = (id) => {
    const product = this.getItem(id);
    this.setState(() => {
      return { modalProduct: product, openModal: true };
    });
  };

  closeModal = (id) => {
    this.setState(() => {
      return { modalOpen: false };
    });
  };

Cart.js:

import React from "react";
import CartColumns from "./CartColumns";
import CartList from "./CartList";
import EmptyCart from "./EmptyCart";

import { ProductContext } from "../App";

export default class Cart extends React.Component {
  render() {
    return (
      <div>
        <ProductContext.Consumer>
          {(value) => {
            console.log(value, "inside Product COnt");
            if (value.length > 0) {
              return (
                <div>
                  <CartColumns />
                  <CartList items={items} />
                </div>
              );
            } else {
              <EmptyCart />;
            }
          }}
        </ProductContext.Consumer>
      </div>
    );
  }
}

CartList.js:

import React from "react";
import CartItem from "./CartItem";

export default function CartList(props) {
  const { items } = props;

  return (
    <div>
      {items.cart.map((item) => (
        <CartItem
          key={item.id}
          item={item}
          increment={item.increment}
          decrement={item.decrement}
        />
      ))}
    </div>
  );
}

CartItem.js:

import React from "react";

function CartItem(props) {
  const { id, title, img, price, total, count } = props.item;
  const { increment, decrement, removeItem } = props;

  return (
    <div className="row my-1 text-capitalize text-center">
      <div className="col-10 mx-auto col-lg-2">
        <img
          src={img}
          style={{ width: "5rem", heigth: "5rem" }}
          className="img-fluid"
          alt=""
        />
      </div>
      <div className="col-10 mx-auto col-lg-2 ">
        <span className="d-lg-none">product :</span> {title}
      </div>
      <div className="col-10 mx-auto col-lg-2 ">
        <strong>
          <span className="d-lg-none">price :</span> ${price}
        </strong>
      </div>
      <div className="col-10 mx-auto col-lg-2 my-2 my-lg-0 ">
        <div className="d-flex justify-content-center">
          <div>
            <span className="btn btn-black mx-1">-</span>
            <span className="btn btn-black mx-1">{count}</span>
            <span className="btn btn-black mx-1">+</span>
          </div>
        </div>
      </div>
      <div className="col-10 mx-auto col-lg-2 ">
        <div className=" cart-icon">
          <i className="fas fa-trash" />
        </div>
      </div>

      <div className="col-10 mx-auto col-lg-2 ">
        <strong>item total : ${total} </strong>
      </div>
    </div>
  );
}

export default CartItem;

Sandbox link for better observation: https://codesandbox.io/s/cart-code-addict-forked-l6tfm?file=/src/cart/CartItem.js

Answer 1

There were few issues

Change following

this.setState(() => {
    return (
        { products: tempProducts, cart: [...this.state.cart, product] },
        () => console.log(this.state)
    );
});

to

this.setState(
    {
        products: tempProducts,
        cart: [...this.state.cart, product]
    },
    () => console.log(this.state)
);

And need to use value.cart to check for length and when passing as a prop.

Instead of

if (value.length > 0) {
    return (
        <div>
            <CartColumns />
            <CartList items={items} />
        </div>
    );
}

It should be

if (value.cart.length > 0) {
    return (
        <div>
            <CartColumns />
            <CartList items={value.cart} />
        </div>
    );
}

And in CartList ,

Instead of

{
    items.cart.map(item => (
        <CartItem
            key={item.id}
            item={item}
            increment={item.increment}
            decrement={item.decrement}
        />
    ));
}

it should be

{
    items.map(item => (
        <CartItem
            key={item.id}
            item={item}
            increment={item.increment}
            decrement={item.decrement}
        />
    ));
}

Now it shows the cart with items

Code sandbox => https://codesandbox.io/s/cart-code-addict-forked-c3kug?file=/src/cart/CartList.js