Angular2 HTTP - How to understand that the backend server is down : <p>I am developing a front end which consumes JSON services provided by a server. </p>

<p>I happily use HTTP of Angular2 and I can catch errors via <code>.catch()</code> operator.</p>

<p>If I find a problem related to a specific service (e.g. the service is not defined by the server) the <code>catch()</code> operator receives a <code>Response</code> with status <code>404</code> and I can easily manage the situation.</p>

<p>On the other hand, if it is the server that is completely down, the <code>catch()</code> operator receives a Response with status code <code>200</code>and no specific sign or text related to the cause of the problem (which is that the whole server is down).
On the console I see that angular (<strong>http.dev.js</strong>) writes a message <code>net::ERR_CONNECTION_REFUSED</code> but I do not know how to do something similar (i.e. understand what is happening and react appropriately) from within my code. </p>

<p>Any help would be appreciated.</p>
