How to add multiple headers in Angular 5 HttpInterceptor

Question

I\'m trying to learn how to use HttpInterceptor to add a couple of headers to each HTTP request the app do to the API. I\'ve got this interceptor:

Answer 1

Since the set method returns headers object every time, you can do this. This way, original headers from the intercepted request will also be retained.

const authReq = req.clone({
    headers: req.headers.set('Content-Type', 'application/json')
    .set('header2', 'header 2 value')
    .set('header3', 'header 3 value')
});