angular 8: "Schematic "interceptor" not found in collection" error while generating interceptor in Angular cli

Question

I am executing command

ng g interceptor error

where error is the name of interceptor

but facing the issue as below:

An unhandled exception occurred: Schematic "interceptor" not found in collection "@schematics/angular".

Do we have to install any package first ?

Answer 1

Looks like schematic support for generating interceptors was added in CLI 9.0.0

So, you can either upgrade to Angular 9, or write your own custom schematic, though in the short-term, if you can't / don't want to upgrade to Angular 9, it's probably easier to just write your interceptor yourself instead of generating it.

Answer 2

If someone looking to create a loading interceptor. Below here is a sample Loading interceptor create it like below and then inject LoadingInterceptor, LoadingIndicatorInterceptor in the provider's array of the parent module.

import { LoadingIndicatorService } from './file-path';
import { Injectable } from '@angular/core';
import {
    HttpEvent,
    HTTP_INTERCEPTORS,
    HttpInterceptor,
    HttpHandler,
    HttpRequest,
  } from '@angular/common/http';
  import { Observable } from 'rxjs';
  import { finalize, tap } from 'rxjs/operators';


@Injectable()
export class LoadingIndicatorInterceptor implements HttpInterceptor {

  constructor(public loadingIndicatorService: LoadingIndicatorService) {}

  intercept (req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // emit onStarted event before request execution
    this.loadingIndicatorService.onStarted(req);

    return next
      .handle(req)
      // emit onFinished event after request execution
      .pipe(
        finalize(() => this.loadingIndicatorService.onFinished(req)), tap( r => {
        })
      );
  }
}

export const LoadingInterceptor = {
  provide: HTTP_INTERCEPTORS,
  useClass: LoadingIndicatorInterceptor,
  multi: true,
};

providers: [ LoadingInterceptor, LoadingIndicatorInterceptor] // This line should be in your module that you want the interceptor to be available