Angular CLI - Typescript throws: Cannot read property 'length' of undefined

Question

I run in angular 4 project with ng serve and i get error

Cannot read property 'length' of undefined 

but I don't have any property length in my project..

the full error

    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> 

package.json

{   "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"   } } 

Answer 1

You might be missing one or more files that typescript is trying to process. To find out which file you are missing just add

console.log(fileName);

at the starting of the createSourceFile function at node_modules/typescript/lib/typescript.js file.

Answer 2

My error was caused by c&p error when creating a small component. I forgot to change path to component's template and styles.