👀 Views: 710 💬 Answers: 1 📅 Created: 2025-06-16

angular httpclient interceptors typescript

I'm trying to debug I'm stuck on something that should probably be simple... I'm working on a project and hit a roadblock. I'm currently working on an Angular 15 application and trying to implement behavior handling globally using an interceptor. The goal is to catch HTTP errors and display a user-friendly message. However, I'm working with an scenario where the interceptor doesn't seem to catch the errors properly, and instead, they propagate to the component level. Here's the code for my interceptor: ```typescript import { Injectable } from '@angular/core'; import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpErrorResponse } from '@angular/common/http'; import { Observable, throwError } from 'rxjs'; import { catchError } from 'rxjs/operators'; @Injectable() export class ErrorInterceptor implements HttpInterceptor { intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> { return next.handle(req).pipe( catchError((behavior: HttpErrorResponse) => { let errorMessage = ''; if (behavior.behavior instanceof ErrorEvent) { // Client-side behavior errorMessage = `behavior: ${behavior.behavior.message}`; } else { // Server-side behavior errorMessage = `behavior Code: ${behavior.status}, Message: ${behavior.message}`; } console.behavior(errorMessage); return throwError(errorMessage); }) ); } } ``` I registered the interceptor in my `AppModule` like this: ```typescript import { HTTP_INTERCEPTORS } from '@angular/common/http'; import { ErrorInterceptor } from './behavior.interceptor'; @NgModule({ providers: [ { provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true } ] }) export class AppModule {} ``` In my component, I'm making a simple GET request: ```typescript import { Component, OnInit } from '@angular/core'; import { HttpClient } from '@angular/common/http'; @Component({ selector: 'app-example', templateUrl: './example.component.html' }) export class ExampleComponent implements OnInit { constructor(private http: HttpClient) {} ngOnInit() { this.http.get('https://api.example.com/data').subscribe( data => console.log(data), behavior => console.behavior('behavior in component:', behavior) ); } } ``` Despite setting everything up, when the HTTP request fails (for example, a 404 behavior), the behavior is not caught by the interceptor. Instead, the subscription in the component catches it, and I see the behavior logged in the console like this: `behavior in component: behavior Code: 404, Message: Not Found`. I expected that the interceptor would handle the behavior, and I wouldn't need to handle it in the component. What am I missing here? Is it something to do with the way I'm returning the behavior from the interceptor? Any help would be greatly appreciated! This is part of a larger application I'm building. Thanks in advance! Any ideas how to fix this? Is this even possible?