由于解析错误，无法获取正确的输出答案

【问题标题】：Not able fetch the right output because of the parsing error由于解析错误，无法获取正确的输出
【发布时间】：2022-01-13 23:22:55
【问题描述】：

import logo from "./logo.svg";
import "./App.css";
import Navbar from "./Components/Navbar";
import ProductList from "./Components/ProductList";
import React, { useState } from "react";

function App() {
  const productList = [
    {
      price: 9999,
      name: "IPhone 10S Max",
      quantity: 0,
    },
    {
      price: 999,
      name: "Redmi Note 10S Max",
      quantity: 0,
    },
  ];

  let [productList , setProductList] = useState(productList);

  const incrementQuantity = (index) => {
    let newProductList = [...productList];
    newProductList[index].quantity++;
    setProductList(newProductList);
  };

  const decrementQuantity = (index) => {
    let newProductList = [...productList];
    newProductList[index].quantity > 0
      ? newProductList[index].quantity--
      : (newProductList[index].quantity = 0);
    setProductList(newProductList);
  };

  return (
    <>
      <Navbar />
      <main className="container mt-5">
        <ProductList
          productList={productList}
          incrementQuantity={incrementQuantity}
          decrementQuantity={decrementQuantity}
        />
      </main>

      {/*<Footer/>*/}
    </>
  );
}

export default App;



**Line 21:7:  Parsing error: Identifier 'productList' has already been declared. (21:7)**

由于解析错误，无法获取正确的输出。

【问题讨论】：

哦，我的上帝...您是否试图通过全部大写并一遍又一遍地复制粘贴相同的句子来获得任何答案？请不要在任何地方再次这样做。

标签： node.js reactjs react-native parsing node-modules

【解决方案1】：

您的值的状态名称与对象名称相同：

//try to name it smth like initialProductList and pass it to useState(initalProductList)
const productList = [ 
    {
      price: 9999,
      name: "IPhone 10S Max",
      quantity: 0,
    },
    {
      price: 999,
      name: "Redmi Note 10S Max",
      quantity: 0,
    },
  ];

  let [productList , setProductList] = useState(productList);

另外，
useState() 应定义为 const，如下所示：

const [productList , setProductList] = useState(productList);

【讨论】：