Whenever you do an request, there are things that could go wrong. If things go wrong the request will return a response with an error code. Based on this error code you for example want to inform the user what went wrong. HTTP Read this instead: Looking for an Angular 4.3+ solution? https://medium.com/@luukgruijs/global-http-error-catching-in-angular-4-3-9e15cc1e0a6b You can only deal with errors if you attach a to your request. This can possibly look like this: catch When your application grows, the amount of HTTP requests increases as well. Attaching a to every request is not exactly DRY. We can fix this by extending the HTTP class from and attach a to the method. catch Angular catch request Creating the HTTPInterceptor class You might already have such a class in your Angular project as we can use such a class as well to for example attach specific headers to each request. If you don’t have one yet, let’s create one now: In this class we overwrite the method with our own implementation. Our implementation attaches a catch to each request and exposes a method. Every response that ends up in the will be passed into this method. This method has to return an in order to work. request handleError catch Observable Now it’s important to make every request use our class instead of the default class. Lucky for us, this is quite easy: HttpInterceptor Http As you can see we updated our constructor. is now of class . We also removed the catch in our request, as that is now handled by the . http HttpInceptor HttpInterceptor Conclusion Using the class we can easily attach a catch to all requests and make sure that potential errors are taken care of properly. HttpInterceptor Thanks for reading. Any feedback? Let me know. Follow me on Medium and let’s connect on LinkedIn
