Function provideHttpClient

packages/common/http/src/provider.ts:99–145

(
  ...features: HttpFeature<HttpFeatureKind>[]
)

 * @see {@link withXhr}
 */
export function provideHttpClient(
  ...features: HttpFeature<HttpFeatureKind>[]
): EnvironmentProviders {
  if (ngDevMode) {
    const featureKinds = new Set(features.map((f) => f.ɵkind));
    if (
      featureKinds.has(HttpFeatureKind.NoXsrfProtection) &&
      featureKinds.has(HttpFeatureKind.CustomXsrfConfiguration)
    ) {
      throw new Error(
        `Configuration error: found both withXsrfConfiguration() and withNoXsrfProtection() in the same call to provideHttpClient(), which is a contradiction.`,
      );
    }

    const hasBackendOverride =
      featureKinds.has(HttpFeatureKind.Fetch) || featureKinds.has(HttpFeatureKind.Xhr);
    if (featureKinds.has(HttpFeatureKind.RequestsMadeViaParent) && hasBackendOverride) {
      throw new Error(
        `Configuration error: withRequestsMadeViaParent() cannot be combined with withFetch() or withXhr() in the same call to provideHttpClient().`,
      );
    }
  }

  const providers: Provider[] = [
    HttpClient,
    FetchBackend,
    HttpInterceptorHandler,
    {provide: HttpHandler, useExisting: HttpInterceptorHandler},
    {
      provide: HttpBackend,
      useFactory: () => {
        return inject(FetchBackend);
      },
    },
    {
      provide: HTTP_INTERCEPTOR_FNS,
      useValue: xsrfInterceptorFn,
      multi: true,
    },
  ];

  for (const feature of features) {
    providers.push(...feature.ɵproviders);
  }

  return makeEnvironmentProviders(providers);
}

/**
 * Adds one or more functional-style HTTP interceptors to the configuration of the `HttpClient`