Angular 15: Issues with Handling HTTP Interceptors and Response Transformations
I can't seem to get I've spent hours debugging this and I'm sure I'm missing something obvious here, but Hey everyone, I'm running into an issue that's driving me crazy... I'm facing a challenge with HTTP interceptors in Angular 15 when trying to transform the response data before it reaches my components. I've implemented an interceptor to add a custom header for authorization and am attempting to modify the response by normalizing the data structure. However, it seems that the transformation does not apply correctly, and I consistently receive the original response format in my components instead of the modified one. Here is my interceptor code: ```typescript import { Injectable } from '@angular/core'; import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse } from '@angular/common/http'; import { Observable } from 'rxjs'; import { tap } from 'rxjs/operators'; @Injectable() export class CustomInterceptor implements HttpInterceptor { intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> { const cloned = req.clone({ setHeaders: { Authorization: `Bearer ${myToken}` } }); return next.handle(cloned).pipe( tap(event => { if (event instanceof HttpResponse) { // Attempting to transform response here const modifiedBody = this.transformResponse(event.body); event = event.clone({ body: modifiedBody }); // This does not seem to work } }) ); } private transformResponse(data: any): any { // Example transformation return { transformedData: data.items, total: data.count }; } } ``` In my component, I have this service call: ```typescript this.myService.getData().subscribe(response => { console.log('Response:', response); // This logs the original response }); ``` Despite the transformation logic being in place, the console still shows the unmodified response data structure. I’ve verified that the interceptor is being called, and the headers are being added correctly. I tried using the `tap` operator to modify the response, but it seems the change isn't reflected in the observable chain. I also considered using `map` instead of `tap`, but I wasn’t sure how to properly manage the observable stream in that case. Any suggestions on how to ensure that my response data is modified correctly before it's returned to the component would be greatly appreciated! What's the best practice here? This is part of a larger application I'm building. Any ideas what could be causing this? This is happening in both development and production on Ubuntu 20.04. I'm open to any suggestions. I've been using Typescript for about a year now. What am I doing wrong?