title: React NextJS app, installed webpack, then removed it: Error: Cannot find module 'webpack/lib/node/NodeOutputFileSystem'
body: <p>While trying to figure out how to create and use ENV secrets with a frontend only ReactJS / NextJS app I broke my app installing webpack.</p>
  
  <p><a href="https://medium.com/@trekinbami/using-environment-variables-in-react-6b0a99d83cf5" rel="noreferrer">https://medium.com/@trekinbami/using-environment-variables-in-react-6b0a99d83cf5</a></p>
  
  <p><a href="https://github.com/zeit/next.js/issues/805" rel="noreferrer">https://github.com/zeit/next.js/issues/805</a></p>
  
  <p>After I <code>npm install webpack</code> I realized that I should not install webpack myself since that is already handled by NextJS.</p>
  
  <p>So I removed my node_modules folder, removed webpack from my package.json, but now when I try to run my app with: <code>npm run dev</code> I get the following error:</p>
  
  <pre><code>moonholdings.io [actionsReducers●] % npm run dev
  
  &gt; moon.holdings@2.0.0 dev /Users/leongaban/projects/Futuratum/moonholdings.io
  &gt; next -p 7777
  
  { Error: Cannot find module 'webpack/lib/node/NodeOutputFileSystem'
      at Function.Module._resolveFilename (internal/modules/cjs/loader.js:581:15)
      at Function.Module._load (internal/modules/cjs/loader.js:507:25)
      at Module.require (internal/modules/cjs/loader.js:637:17)
      at require (internal/modules/cjs/helpers.js:20:18)
      at Object.&lt;anonymous&gt; (/Users/leongaban/projects/Futuratum/moonholdings.io/node_modules/webpack-dev-middleware/lib/fs.js:7:30)
      at Module._compile (internal/modules/cjs/loader.js:689:30)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
      at Module.load (internal/modules/cjs/loader.js:599:32)
      at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
      at Function.Module._load (internal/modules/cjs/loader.js:530:3) code: 'MODULE_NOT_FOUND' }
  </code></pre>
  
  <p>Thoughts on why this would be happening?</p>
  
  <p><strong>My next.config.js</strong></p>
  
  <pre><code>const { PHASE_PRODUCTION_SERVER } =
    process.env.NODE_ENV === 'development'
      ? {}
      : !process.env.NOW_REGION
        ? require('next/constants')
        : require('next-server/constants');
  
  module.exports = (phase, { defaultConfig }) =&gt; {
    if (phase === PHASE_PRODUCTION_SERVER) {
      // Config used to run in production.
      return {};
    }
  
    // ✅ Put the require call here.
    const withTypescript = require('@zeit/next-typescript');
    const withCSS = require('@zeit/next-sass');
  
    return withTypescript(withCSS());
  };
  </code></pre>
  
  <p><strong>package.json</strong></p>
  
  <pre><code>{
    "name": "moon.holdings",
    "version": "2.0.0",
    "description": "Moon Holdings, your cryptocurrency portfolio.",
    "main": "index.js",
    "scripts": {
      "dev": "next -p 7777",
      "build": "next build",
      "start": "next start -p 8000",
      "test": "NODE_ENV=test jest --watch --no-cache",
      "test-win": "SET NODE_ENV=test&amp;&amp; jest --watch",
      "heroku-postbuild": "next build"
    },
    "author": "Futuratum",
    "license": "ISC",
    "dependencies": {
      "@zeit/next-sass": "^1.0.1",
      "@zeit/next-typescript": "^1.1.1",
      "apollo-boost": "^0.1.16",
      "apollo-client": "^2.4.2",
      "axios": "^0.18.0",
      "decko": "^1.2.0",
      "downshift": "^2.2.3",
      "enzyme": "^3.6.0",
      "enzyme-adapter-react-16": "^1.5.0",
      "graphql": "^14.0.2",
      "graphql-tag": "^2.9.2",
      "graphql-tools": "^4.0.0",
      "lodash.debounce": "^4.0.8",
      "next": "^7.0.2",
      "next-with-apollo": "^3.1.3",
      "node-sass": "^4.11.0",
      "nprogress": "^0.2.0",
      "prop-types": "^15.6.2",
      "ramda": "^0.26.1",
      "react": "^16.7.0",
      "react-adopt": "^0.6.0",
      "react-apollo": "^2.2.1",
      "react-dom": "^16.7.0",
      "react-redux": "^6.0.0",
      "react-transition-group": "^2.5.0",
      "redux-devtools-extension": "^2.13.8",
      "redux-thunk": "^2.3.0",
      "styled-components": "^3.4.9",
      "tslint": "^5.12.1",
      "tslint-react": "^3.6.0",
      "typescript": "^3.2.4",
      "waait": "^1.0.2"
    },
    "devDependencies": {
      "@babel/plugin-proposal-decorators": "^7.3.0",
      "@babel/preset-typescript": "^7.1.0",
      "@types/enzyme": "^3.1.15",
      "@types/jest": "^23.3.13",
      "@types/next": "^7.0.6",
      "@types/ramda": "^0.25.49",
      "@types/react": "^16.7.20",
      "@types/react-dom": "^16.0.11",
      "@types/react-redux": "^7.0.1",
      "@types/zeit__next-typescript": "^0.1.1",
      "babel-core": "^7.0.0-bridge.0",
      "babel-jest": "^23.6.0",
      "babel-plugin-sass-vars": "^0.2.1",
      "babel-plugin-styled-components": "^1.7.1",
      "casual": "^1.5.19",
      "enzyme-to-json": "^3.3.4",
      "jest": "^23.6.0",
      "jest-transform-graphql": "^2.1.0"
    },
    "jest": {
      "setupTestFrameworkScriptFile": "&lt;rootDir&gt;/jest.setup.js",
      "testPathIgnorePatterns": [
        "&lt;rootDir&gt;/.next/",
        "&lt;rootDir&gt;/node_modules/"
      ],
      "transform": {
        ".*": "babel-jest",
        "^.+\\.js?$": "babel-jest",
        "^.+\\.ts?$": "babel-jest",
        "^.+\\.tsx?$": "babel-jest"
      },
      "moduleFileExtensions": [
        "js",
        "json",
        "ts",
        "tsx"
      ],
      "modulePaths": [
        "&lt;rootDir&gt;/components/",
        "&lt;rootDir&gt;/pages/",
        "&lt;rootDir&gt;/shared/"
      ]
    }
  }
  </code></pre>