Angular, Http GET with parameter?

Having something like this:

let headers = new Headers();
headers.append('Content-Type', 'application/json');
headers.append('projectid', this.id);
let params = new URLSearchParams();
params.append("someParamKey", this.someParamValue)

this.http.get('http://localhost:63203/api/CallCenter/GetSupport', { headers: headers, search: params })

Of course, appending every param you need to params. It gives you a lot more flexibility than just using a URL string to pass params to the request.

EDIT(28.09.2017): As Al-Mothafar stated in a comment, search is deprecated as of Angular 4, so you should use params

EDIT(02.11.2017): If you are using the new HttpClient there are now HttpParams, which look and are used like this:

let params = new HttpParams().set("paramName",paramValue).set("paramName2", paramValue2); //Create new HttpParams

And then add the params to the request in, basically, the same way:

this.http.get(url, {headers: headers, params: params}); 
//No need to use .map(res => res.json()) anymore

More in the docs for HttpParams and HttpClient

For Angular 9+ You can add headers and params directly without the key-value notion:

const headers = new HttpHeaders().append('header', 'value');
const params = new HttpParams().append('param', 'value');
this.http.get('url', {headers, params});