title: TypeError: Cannot read property 'flags' of undefined
body: <p>After cloning a repo, <code>npm install</code> &amp;&amp; <code>ionic cordova build android --prod</code> shows me following error.</p>
  
  <pre><code>TypeError: Cannot read property 'flags' of undefined
      at checkUnreachable (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:24905:31)
      at bindChildrenWorker (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:23111:17)
      at bindChildren (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:23055:17)
      at bind (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:24319:21)
      at bindSourceFile
  </code></pre>
  
  <p>I am sure it worked well without any problems before. Here are my system information and package.json.</p>
  
  <blockquote>
    <p>System:</p>
  
  <pre><code>    Node : v8.10.0
      npm  : 5.6.0
      OS   : Windows 10
  </code></pre>
    
    <p>Package.json:</p>
  
  <pre><code>"dependencies": {
      "@angular/common": "5.0.3",
      "@angular/compiler": "5.0.3",
      "@angular/compiler-cli": "5.0.3",
      "@angular/core": "5.0.3",
      "@angular/forms": "5.0.3",
      "@angular/http": "5.0.3",
      "@angular/platform-browser": "5.0.3",
      "@angular/platform-browser-dynamic": "5.0.3",
      "@ionic-native/core": "^4.5.2",
      "@ionic-native/facebook": "^4.5.2",
      "@ionic-native/firebase": "^4.5.2",
      "@ionic-native/in-app-browser": "^4.5.2",
      "@ionic-native/in-app-purchase": "^4.5.2",
      "@ionic-native/intercom": "^4.5.2",
      "@ionic-native/social-sharing": "^4.5.2",
      "@ionic-native/splash-screen": "4.4.0",
      "@ionic-native/status-bar": "4.4.0",
      "@ionic/storage": "2.1.3",
      "angularfire2": "^5.0.0-rc.6",
      "firebase": "^4.12.0",
      "ionic-angular": "3.9.2",
      "ionicons": "3.0.0",
      "raven-js": "^3.17.0",
      "rxjs": "5.5.2",
      "sw-toolbox": "3.6.0",
      "zone.js": "^0.8.18"
    },
    "devDependencies": {
      "@angular/cli": "^1.7.3",
      "@ionic/app-scripts": "^3.1.8",
      "@types/jasmine": "2.8.4",
      "@types/node": "9.3.0",
      "html-loader": "0.5.5",
      "istanbul-instrumenter-loader": "3.0.0",
      "jasmine": "2.9.0",
      "jasmine-spec-reporter": "4.2.1",
      "karma": "2.0.0",
      "karma-chrome-launcher": "2.2.0",
      "karma-coverage-istanbul-reporter": "1.3.3",
      "karma-jasmine": "1.1.1",
      "karma-jasmine-html-reporter": "0.2.2",
      "karma-sourcemap-loader": "0.3.7",
      "karma-webpack": "2.0.9",
      "protractor": "5.2.2",
      "ts-loader": "3.2.0",
      "ts-node": "4.1.0",
      "tslint": "5.9.1",
      "typescript": "2.4.2"
    },
  </code></pre>
  </blockquote>
  
  <p>I guess this problem is related with <code>@ionic/app-scripts</code> <a href="https://github.com/ionic-team/ionic-app-scripts/issues/1347" rel="nofollow noreferrer">issue</a>.</p>