title: 'npm start' with create-react-app not launching server on macOS
body: <p>After creating an app using create-react-app, I tried using 'npm start' to run the app. Although it doesn't throw an error, it also doesn't launch the server.</p>
  
  <p>For a little context, this command was working a few weeks ago just fine. It would spit out a little bit of text into the console and then lauch a browser at localhost:3000. Since then, I ran into a bug between node and React Native and downgraded to node v10 in order to avoid the bug (although Im currently using node v13). Since then, I have reinstalled node (via homebrew) and reinstalled creact-react-app.</p>
  
  <p>Below are my current specifications</p>
  
  <blockquote>
    <p>macOS v10.14.5</p>
    
    <p>node v13.5.0</p>
    
    <p>npm v6.13.4</p>
    
    <p>create-react-app v3.3.0</p>
  </blockquote>
  
  <p>Below is my package.json file</p>
  
  <pre><code>{
    "name": "testing",
    "version": "0.1.0",
    "private": true,
    "dependencies": {
      "@testing-library/jest-dom": "^4.2.4",
      "@testing-library/react": "^9.4.0",
      "@testing-library/user-event": "^7.2.1",
      "react": "^16.12.0",
      "react-dom": "^16.12.0",
      "react-scripts": "3.3.0"
    },
    "scripts": {
      "start": "react-scripts start",
      "build": "react-scripts build",
      "test": "react-scripts test",
      "eject": "react-scripts eject"
    },
    "eslintConfig": {
      "extends": "react-app"
    },
    "browserslist": {
      "production": [
        "&gt;0.2%",
        "not dead",
        "not op_mini all"
      ],
      "development": [
        "last 1 chrome version",
        "last 1 firefox version",
        "last 1 safari version"
      ]
    }
  }
  </code></pre>
  
  <p>I have tried using npm-install-missing to check for missing dependancies. I have also tried removing node modules using 'rm -rf node_modules' and then running 'npm install'.</p>
  
  <p>I am unsure where to go from here. I thought that since 'npm start' calls 'react-scripts start', maybe there was an issue within react-scripts. However, react-scripts should have been reinstalled with create-react-app so im not sure. I am happy to provide more information if there is anything else that I am missing. Thanks!</p>
  
  <p><strong>Edit:</strong> When I deleted a previous version of node, I went though and deleted files manulally so that I could reinstall node using homebrew. I thought that I deleted all the proper files, however, if I didn't, could that play a role in this?</p>