Handling API errors and invalid responses in Angular

An unfortunate side effect of relying on external data sources for an application is that they can sometimes let us down. Service outages, API changes, and even network latency can all result in errors in API requests that have to be dealt with in our application. Luckily, promises have a built-in support for error handling that we can leverage to handle these situations.

Getting ready

Let's make our blog post metadata request fail by failing to pass its API key. Google's Blogger API requires a valid API key for any request to it. By removing it, we can simulate an error for when our request doesn't go as expected.

How to do it...

Let's perform the following steps to add error handling to our blog post service API:

1. First, let's create an error handler in our /src/app/posts/blog-post.service.ts service. Since our error handler is for our promise-based HTTP requests, we will also make this handler return a promise object. This error handler will...