title: How do I construct params for a get request?
body: <p>I am trying to do:</p>
  <pre><code>export interface ApiCallOptions {
    abc: string,
    xyz: number
  }
  makeRequest (options: ApiCallOptions) {
    return this.http.get('/some/path/to/endpoint', { params: options });
  }
  </code></pre>
  <p>I get an error that ApiCallOptions isn't a HttpParams object...  I tried casting options as HttpParams, still fails..</p>
  <p>So then I tried:</p>
  <pre><code>  const params = new HttpParams({ fromObject: options });
    return this.http.get('/some/path/to/endpoint', { params: params });
  </code></pre>
  <p>And I get:</p>
  <blockquote>
  <p>The expected type comes from property 'fromObject' which is declared
  here on type 'HttpParamsOptions'</p>
  </blockquote>
  <p>What am I doing wrong?</p>