MatToolbar throws error when using it with Angular 9

Question

Angular version 9.2.0

When I import the MatToolbarModule in a module and use it in the html template, then I get the following error message:

This likely means that the library (@angular/material/toolbar) which declares MatToolbarModule has not been processed correctly by ngcc, or is not compatible with Angular Ivy. Check if a newer version of the library is available, and update if so. Also consider checking with the library's authors to see if the library is expected to be compatible with Ivy.

8 export declare class MatToolbarModule {                        ~~~~~~~~~~~~~~~~ src/app/angular-material.module.ts:53:14 - error NG6002: Appears in the NgModule.imports of ComponentsModule, but itself has errors 

Does anyone face the same issue?

Answer 1

Add below specific configuration in package.json and npm install.

{   "scripts": {     "postinstall": "ngcc"   } } 

Reference: https://angular.io/guide/ivy#speeding-up-ngcc-compilation

Answer 2

I had the same problem before, its because you modify your app.module.ts file while the server is running. Try to stop it and then run it again using the ng servecommand.