call

http.when('api/1').call(config => {});

The config object contains information such as the method, url, and headers.

If you match a url with a regular expression, any captured groups can be accessed via the match array property.

http.when('post', /^api\/(\d+)\/upload$/).call(function({method, url, match}){
  method === 'post';
  url === 'api/123/upload';
  match[0] === url;
  match[1] === '123';
});