start of error interceptor

src/app/http-interceptors/error.interceptor.spec.ts

@@ -0,0 +1,16 @@
+import { TestBed } from '@angular/core/testing';
+
+import { ErrorInterceptor } from './error.interceptor';
+
+describe('ErrorInterceptor', () => {
+  beforeEach(() => TestBed.configureTestingModule({
+    providers: [
+      ErrorInterceptor
+      ]
+  }));
+
+  it('should be created', () => {
+    const interceptor: ErrorInterceptor = TestBed.inject(ErrorInterceptor);
+    expect(interceptor).toBeTruthy();
+  });
+});

src/app/http-interceptors/error.interceptor.ts

@@ -0,0 +1,36 @@
+import { Injectable } from '@angular/core';
+import {
+  HttpRequest,
+  HttpHandler,
+  HttpEvent,
+  HttpInterceptor,
+  HttpErrorResponse
+} from '@angular/common/http';
+import { Observable, throwError } from 'rxjs';
+import { apiRetry } from '../api-utils';
+import { retry, catchError } from 'rxjs/operators';
+
+@Injectable()
+export class ErrorInterceptor implements HttpInterceptor {
+
+  constructor() { }
+
+  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
+    return next.handle(request)
+      .pipe(
+        retry(apiRetry),
+        catchError((error: HttpErrorResponse) => {
+          let errorMsg: string;
+          if (error.error instanceof ErrorEvent) {
+            // Client side
+            errorMsg = `Error: ${error.error.message}`;
+          } else {
+            // Server side
+            errorMsg = `Error Status: ${error.status}\nMessage: ${error.message}`;
+          }
+          console.log(errorMsg);
+          return throwError(errorMsg);
+        })
+      )
+  }
+}

src/app/http-interceptors/index.ts

@@ -3,10 +3,12 @@ import { HTTP_INTERCEPTORS } from '@angular/common/http';
 
 import { CSRFInterceptor } from './csrf.interceptor';
 import { CachingInterceptor } from './caching.interceptor';
+import { ErrorInterceptor } from './error.interceptor';
 
 /** Http interceptor providers in outside-in order */
 export const httpInterceptorProviders = [
     { provide: HTTP_INTERCEPTORS, useClass: CachingInterceptor, multi: true },
+    { provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true },
     // CSRFInterceptor needs to be last 
     { provide: HTTP_INTERCEPTORS, useClass: CSRFInterceptor, multi: true },
 ];