Working with headers in Express

HTTP headers are a common way for web servers to share information about their content with other servers and web applications. Reading and writing headers can be necessary for a variety of web server needs, including cross-origin resource sharing (CORS).

Getting ready

Let's use HTTP headers to enhance our Express route configurations. For our API routes, we will add headers to enable CORS via pre-flight OPTIONS requests. This will come in handy if we ever need to run our API on a different domain than our Angular web application.

For our Angular routes, we will read the incoming Accept-Language header and parse it into a locale property that we can inject into our index.html file&apos...