How to Prevent Returning HTML in Angular: A Developer’s Guide (Without Losing Your Sanity 😱)

Hey there, fellow coders! 👋 Sharih Hassan here—your friendly neighborhood developer and blogger at SharihHassan.com. Today, we’re tackling a quirky little problem that’s haunted many Angular devs: how to stop your app from returning HTML when you specifically asked for JSON. Let’s turn that frustration into action—and maybe share a laugh along the way.

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Wait, Why Am I Getting HTML Instead of Data? 🤔

Picture this: You’re happily coding an Angular app, sipping coffee ☕, and suddenly your API call returns… an entire HTML page instead of that sweet, sweet JSON. It’s like ordering a latte and getting a cactus 🌵. Not cool.

This usually happens when:

• Your API endpoint is misconfigured (oops).
• The server throws an error (like a 404 or 500) and dumps HTML instead of JSON.
• You’ve accidentally called the wrong URL (been there, done that 💁♂️).

But fear not! Let’s fix this faster than you can say, “Why is my app rendering a 404 page?!”

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Step 1: Check Your Endpoints (No, Seriously)

First, channel your inner detective 🕵️♂️. Did you typo the API URL? Check your environment.ts file or wherever you store endpoints. A misplaced / can turn your data fetch into a wild goose chase.

Typescript

// environment.ts  
export const environment = {  
  production: false,  
  apiUrl: 'https://your-api.com/data' // Not 'https://your-api.com/data/' 🙅♂️  
};  

Pro tip: Use Angular’s HttpClient with error handling to catch these gremlins early:

Typescript

getData() {  
  return this.http.get(environment.apiUrl).pipe(  
    catchError((error) => {  
      console.log("Hey, why is there HTML here?! 🔍", error);  
      throw error;  
    })  
  );  
}  

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Step 2: Forcefully Reject HTML Responses

Sometimes, servers get too helpful and return HTML even on errors. To avoid this, explicitly ask for JSON in your HTTP headers:

Typescript

getData() {  
  const headers = new HttpHeaders({  
    'Accept': 'application/json' // "I said JSON, please!" 📢  
  });  
  return this.http.get(environment.apiUrl, { headers });  
}  

If the server still sends HTML, it’s time to yell at your backend team. Politely, of course. 😇

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Step 3: Validate Responses Like a Bouncer 🚧

Don’t trust strangers—even your API. Use Angular’s interceptors to validate responses before they wreak havoc:

Typescript

intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {  
  return next.handle(req).pipe(  
    filter(event => event instanceof HttpResponse),  
    map((event: HttpResponse<any>) => {  
      if (event.headers.get('Content-Type')?.includes('text/html')) {  
        throw new Error('HTML detected! Abort! Abort! 🚨');  
      }  
      return event;  
    })  
  );  
}  

Now your app will block HTML at the door like an overzealous nightclub bouncer.

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Step 4: Handle Errors Gracefully (Because Stuff Happens)

Even with precautions, errors happen. Maybe the server is down, or a cat walked on the keyboard 🐱💻. Use Angular’s error handling to show friendly messages instead of raw HTML:

Typescript

this.dataService.getData().subscribe({  
  next: (data) => this.showData(data),  
  error: (err) => {  
    this.displayError("Oops! Our hamsters took a break. 🐹 Try again later!");  
  }  
});  

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Step 5: Server-Side Fixes (Because Teamwork Makes the Dream Work)

If you control the backend, ensure it never returns HTML for API routes. For example, in Node.js/Express:

Javascript

app.use('/api', (req, res, next) => {  
  res.status(404).json({ error: 'Not Found' }); // Not res.sendFile('404.html')!  
});  

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Final Thoughts: Keep Calm and Code On 💪

Returning HTML instead of JSON is like getting socks for Christmas—unexpected and mildly infuriating. But with proper error handling, headers, and teamwork, you’ll squash this bug faster than you can say, “Where’s my data?!”

By the way, if you’re into quirky JavaScript hacks, check out my previous article on How to Simulate Keyboard Typing in the JavaScript Console. It’s a fun little trick that’ll make you feel like a coding wizard 🧙‍♂️.

Catch you in the next post!
– Sharih Hassan ✌️