title: cannot start a react project with yarn start
body: <p>I create react app with create-react-app and when I use yarn start the following error happens:</p>
  <p><a href="https://i.stack.imgur.com/Rv4lV.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Rv4lV.jpg" alt="" /></a></p>
  <p>Here is the package.json of the project folder:</p>
  <pre><code>{
    &quot;name&quot;: &quot;letmeask&quot;,
    &quot;version&quot;: &quot;0.1.0&quot;,
    &quot;private&quot;: true,
    &quot;dependencies&quot;: {
      &quot;@testing-library/jest-dom&quot;: &quot;^5.11.4&quot;,
      &quot;@testing-library/react&quot;: &quot;^11.1.0&quot;,
      &quot;@testing-library/user-event&quot;: &quot;^12.1.10&quot;,
      &quot;@types/jest&quot;: &quot;^26.0.15&quot;,
      &quot;@types/node&quot;: &quot;^12.0.0&quot;,
      &quot;@types/react&quot;: &quot;^17.0.0&quot;,
      &quot;@types/react-dom&quot;: &quot;^17.0.0&quot;,
      &quot;react&quot;: &quot;^17.0.2&quot;,
      &quot;react-dom&quot;: &quot;^17.0.2&quot;,
      &quot;react-scripts&quot;: &quot;4.0.3&quot;,
      &quot;typescript&quot;: &quot;^4.1.2&quot;,
      &quot;web-vitals&quot;: &quot;^1.0.1&quot;
    },
    &quot;scripts&quot;: {
      &quot;start&quot;: &quot;react-scripts start&quot;,
      &quot;build&quot;: &quot;react-scripts build&quot;,
      &quot;test&quot;: &quot;react-scripts test&quot;,
      &quot;eject&quot;: &quot;react-scripts eject&quot;
    },
    &quot;eslintConfig&quot;: {
      &quot;extends&quot;: [
        &quot;react-app&quot;,
        &quot;react-app/jest&quot;
      ]
    },
    &quot;browserslist&quot;: {
      &quot;production&quot;: [
        &quot;&gt;0.2%&quot;,
        &quot;not dead&quot;,
        &quot;not op_mini all&quot;
      ],
      &quot;development&quot;: [
        &quot;last 1 chrome version&quot;,
        &quot;last 1 firefox version&quot;,
        &quot;last 1 safari version&quot;
      ]
    }
  }
  </code></pre>
  <p>and here is the package.json from upath folder:</p>
  <pre><code>{
    &quot;name&quot;: &quot;upath&quot;,
    &quot;description&quot;: &quot;A proxy to `path`, replacing `\\` with `/` for all results &amp; new methods to normalize &amp; join keeping leading `./` and add, change, default, trim file extensions.&quot;,
    &quot;version&quot;: &quot;1.2.0&quot;,
    &quot;homepage&quot;: &quot;http://github.com/anodynos/upath/&quot;,
    &quot;author&quot;: {
      &quot;name&quot;: &quot;Angelos Pikoulas&quot;,
      &quot;email&quot;: &quot;agelos.pikoulas@gmail.com&quot;
    },
    &quot;license&quot;: &quot;MIT&quot;,
    &quot;keywords&quot;: [
      &quot;path&quot;,
      &quot;unix&quot;,
      &quot;windows&quot;,
      &quot;extension&quot;,
      &quot;file extension&quot;,
      &quot;replace extension&quot;,
      &quot;change extension&quot;,
      &quot;trim extension&quot;,
      &quot;add extension&quot;,
      &quot;default extension&quot;
    ],
    &quot;repository&quot;: {
      &quot;type&quot;: &quot;git&quot;,
      &quot;url&quot;: &quot;git://github.com/anodynos/upath&quot;
    },
    &quot;bugs&quot;: {
      &quot;url&quot;: &quot;http://github.com/anodynos/upath/issues&quot;,
      &quot;email&quot;: &quot;agelos.pikoulas@gmail.com&quot;
    },
    &quot;main&quot;: &quot;./build/code/upath.js&quot;,
    &quot;types&quot;: &quot;./upath.d.ts&quot;,
    &quot;preferGlobal&quot;: false,
    &quot;scripts&quot;: {
      &quot;test&quot;: &quot;grunt&quot;,
      &quot;build&quot;: &quot;grunt lib&quot;
    },
    &quot;directories&quot;: {
      &quot;doc&quot;: &quot;./doc&quot;,
      &quot;dist&quot;: &quot;./build&quot;
    },
    &quot;engines&quot;: {
      &quot;node&quot;: &quot;&gt;=4&quot;,
      &quot;yarn&quot;: &quot;*&quot;
    },
    &quot;devDependencies&quot;: {
      &quot;chai&quot;: &quot;~4.0.2&quot;,
      &quot;coffee-script&quot;: &quot;1.12.6&quot;,
      &quot;grunt&quot;: &quot;0.4.5&quot;,
      &quot;grunt-contrib-watch&quot;: &quot;^1.1.0&quot;,
      &quot;grunt-urequire&quot;: &quot;0.7.x&quot;,
      &quot;lodash&quot;: &quot;^4.17.15&quot;,
      &quot;mocha&quot;: &quot;~3.4.2&quot;,
      &quot;uberscore&quot;: &quot;0.0.19&quot;,
      &quot;underscore.string&quot;: &quot;^3.3.5&quot;,
      &quot;urequire&quot;: &quot;0.7.0-beta.33&quot;,
      &quot;urequire-ab-specrunner&quot;: &quot;^0.2.5&quot;,
      &quot;urequire-rc-inject-version&quot;: &quot;^0.1.6&quot;
    }
  }
  </code></pre>
  <p>I've tried yarn install, yarn update, npm install, npm upgrade, vscode reinstall, but nothing works.</p>