小编Shu*_*mar的帖子

为什么我收到这个错误？当我选择<li>带有的标签时，如何访问和打印节点querySelectorAll？

script.js:14 Uncaught TypeError: list.map is not a function

HTML

<ul class="wrapper1" id="testDiv">
        <li class="cake">Carrots</li>
        <li class="cake">Cake</li>
        <li class="cake">Wheat</li>
        <li class="cake">Balloons</li>
    </ul>

JS

 let list = document.querySelectorAll("li");
        let items = list.map(elem => {
      console.log(elem);
    })

我使用 create-react-app test 创建了一个名为文件夹的测试，在成功创建文件夹后，在执行 npm start 时出现此错误

Failed to compile.

./src/index.js
Module not found: Can't resolve 'react' in 'C:\Users\USER\Desktop\test\src'

包.json

{
  "name": "test",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "react": "^16.6.3",
    "react-dom": "^16.6.3",
    "react-scripts": "2.1.1"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": [
    ">0.2%",
    "not dead",
    "not ie <= 11",
    "not op_mini all"
  ]
}

我曾尝试删除yarn.lock 文件然后安装yarn，但错误未修复。