title: Angular CLI - Typescript throws: Cannot read property 'length' of undefined
body: <p>I run in angular 4 project with ng serve and i get error</p>
  
  <pre><code>Cannot read property 'length' of undefined
  </code></pre>
  
  <p>but I don't have any property length in my project..</p>
  
  <p>the full error</p>
  
  <pre><code>    Your global Angular CLI version (1.2.1) is greater than your local
  version (1.1.3). The local Angular CLI version is used.
  
  To disable this warning use "ng set --global warnings.versionMismatch=false".
  Cannot read property 'length' of undefined
  TypeError: Cannot read property 'length' of undefined
      at createSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:15457:109)
      at parseSourceFileWorker (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:15389:26)
      at Object.parseSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:15338:26)
      at Object.createSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:15192:29)
      at VirtualFileStats.getSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\@ngtools\webpack\src\compiler_host.js:66:35)
      at WebpackCompilerHost.getSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\@ngtools\webpack\src\compiler_host.js:213:38)
      at findSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67909:29)
      at processImportedModules (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:68056:25)
      at findSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67937:17)
      at processImportedModules (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:68056:25)
      at findSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67937:17)
      at processSourceFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67840:27)
      at processRootFile (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67728:13)
      at E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67018:60
      at Object.forEach (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:1449:30)
      at Object.createProgram (E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master\node_modules\typescript\lib\typescript.js:67018:16)
  PS E:\פרוייקטים\פרוייקטים קיץ\Angular 4\Youtube Channel Angular Firebase\full project of the instructor github\angular-firestarter-master&gt;
  </code></pre>
  
  <p>package.json</p>
  
  <pre><code>{
    "name": "firestarter",
    "version": "0.0.0",
    "license": "MIT",
    "scripts": {
      "ng": "ng",
      "start": "ng serve",
      "build": "ng build",
      "test": "ng test",
      "lint": "ng lint",
      "e2e": "ng e2e"
    },
    "private": true,
    "dependencies": {
      "@angular/animations": "^4.2.4",
      "@angular/common": "^4.2.4",
      "@angular/compiler": "^4.2.4",
      "@angular/core": "^4.2.4",
      "@angular/forms": "^4.2.4",
      "@angular/http": "^4.2.4",
      "@angular/platform-browser": "^4.2.4",
      "@angular/platform-browser-dynamic": "^4.2.4",
      "@angular/platform-server": "^4.2.4",
      "@angular/router": "^4.2.4",
      "@types/lodash": "^4.14.67",
      "angularfire2": "^4.0.0-rc.1",
      "core-js": "^2.4.1",
      "firebase": "^4.1.3",
      "lodash": "^4.17.4",
      "rxjs": "^5.4.1",
      "zone.js": "^0.8.12"
    },
    "devDependencies": {
      "@angular/cli": "^1.1.3",
      "@angular/compiler-cli": "^4.2.4",
      "@types/jasmine": "2.5.53",
      "@types/node": "~8.0.4",
      "codelyzer": "~3.1.1",
      "jasmine-core": "~2.6.4",
      "jasmine-spec-reporter": "~4.1.1",
      "karma": "~1.7.0",
      "karma-chrome-launcher": "~2.2.0",
      "karma-cli": "~1.0.1",
      "karma-coverage-istanbul-reporter": "^1.3.0",
      "karma-jasmine": "~1.1.0",
      "karma-jasmine-html-reporter": "^0.2.2",
      "protractor": "~5.1.2",
      "ts-node": "~3.1.0",
      "tslint": "~5.4.3",
      "typescript": "=2.3.4"
    }
  }
  </code></pre>