ERREUR dans TypeError: impossible de lire la propriété 'flags' de undefined

Question

J'ai un problème lorsque j'essaye d'exécuter ng serve sur un projet Angular) récemment créé. La version que j'utilise est la 9.1.4, cette erreur ne se produit pas sur un projet avec un ancien Angular version.

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.901.4
@angular-devkit/build-angular     0.901.4
@angular-devkit/build-optimizer   0.901.4
@angular-devkit/build-webpack     0.901.4
@angular-devkit/core              9.1.4
@angular-devkit/schematics        9.1.4
@angular/cli                      9.1.4
@ngtools/webpack                  9.1.4
@schematics/angular               9.1.4
@schematics/update                0.901.4
rxjs                              6.5.5
TypeScript                        3.8.3
webpack                           4.42.0

Après avoir exécuté ng serve ou ng build:

chunk {main} main.js, main.js.map (main) 2 kB [initial] [rendered]<br>
chunk {polyfills} polyfills.js, polyfills.js.map (polyfills) 679 bytes [initial] [rendered]<br>
chunk {runtime} runtime.js, runtime.js.map (runtime) 6.15 kB [entry] [rendered]<br>
chunk {styles} styles.js, styles.js.map (styles) 12.4 kB [initial] [rendered]<br>
chunk {vendor} vendor.js, vendor.js.map (vendor) 339 kB [initial] [rendered]<br>
Date: 2020-05-08T02:06:46.145Z - Hash: 1a1b937f0ca2bb37634b - Time: 4087ms<br>

**ERROR in TypeError: Cannot read property 'flags' of undefined**
    at resolveAlias (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:36513:37)
    at checkAliasSymbol (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:64502:26)
    at checkImportBinding (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:64534:13)
    at checkImportDeclaration (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:64552:29)
    at checkSourceElementWorker (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:64961:28)
    at checkSourceElement (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:64800:17)
    at Object.forEach (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:317:30)
    at checkSourceFileWorker (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:65123:20)
    at checkSourceFile (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:65091:13)
    at getDiagnosticsWorker (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:65179:17)
    at Object.getDiagnostics (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:65165:24)
    at C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:98703:85
    at runWithCancellationToken (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:98665:24)
    at getBindAndCheckDiagnosticsForFileNoCache (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:98691:20)
    at getAndCacheDiagnostics (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:98956:26)
    at getBindAndCheckDiagnosticsForFile (C:\Cursos\Angular\ang-hello-world\node_modules\TypeScript\lib\TypeScript.js:98688:20)

** **Angular Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/** **

Le résultat que j'obtiens sur mon navigateur après avoir exécuté ce projet est:

Cannot GET /

Answer 1

essayez cette solution:

npm install @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected] @angular/[email protected]

npm install

ng serve