Angular: HttpClientModule import error (could not be resolved to an NgModule class)

Issue

I was trying to build a simple app with crud on fake json server

but i can't import HttpClientModule

Here is error message from VS Code :

ERROR in node_modules/@angular/common/http/http.d.ts:2801:22 - error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class.

    This likely means that the library (@angular/common/http) which declares HttpClientModule 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 Check if a newer version of the library is available, and update if so.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.

    2801 export declare class HttpClientModule {

Here is app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { EmployeeCreateComponent } from './employee-create/employee-create.component';
import { EmployeeEditComponent } from './employee-edit/employee-edit.component';
import { EmployeeListComponent } from './employee-list/employee-list.component';

import { HttpClientModule } from '@angular/common/http';


@NgModule({
  declarations: [
    AppComponent,
    EmployeeCreateComponent,
    EmployeeEditComponent,
    EmployeeListComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
    AppRoutingModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

app.component.ts

import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'restTest6';
}

note that : I didn't use HttpClientModule anywhere else. I imported and did ng serve -o and got error. Please point out what went wrong

Solution

I had the same problem, I just run the following command and it worked after without any error.

npm cache verify

If it does not, try manually deleting the node_modules folder and reinstalling the modules with npm install.

rm -rf node_modules
npm install

On npm > 6, you can also run npm ci, which also deletes the node_modules folder and reinstall packages after.

Edit As other answers suggested, you may need to restartng serve if the above steps do not work (but they normally do)

Answered By - David