title: wait for Http response in angular 2
body: <p>I am using HTTP request in angular 2. I want when I get HTTP response then next process is called.</p>
  
  <p><strong>Example:</strong> In a <strong>form</strong> <strong>select option</strong> values are coming from <strong>HTTP get Request</strong>.I want to form page is loading until I get response for select options.</p>
  
  <p><strong>get function</strong></p>
  
  <pre><code>getSelectOptionValue(): any {
        let area_list_url = '/select_option_list/';
  
        this.urlGet(area_list_url).subscribe(
          (response) =&gt; {
            let data = response.text() ? response.json() : [{}];
            if (data) {
              Constant.areaList = data;
            }
          }
        );
      }
      return JSON.stringify(Constant.areaList);
    }
  </code></pre>
  
  <p><strong>GET function</strong></p>
  
  <pre><code> urlGet(url: string) {
  
      return this._http.get(Constant.hostUrl + url, {headers: GlobalUtils.head})
        .map((res)=&gt; {
          if (res.status === 200) {
            console.log(res);
            return res;
          } else if (res.status = 201) {
            return res;
          }
        }).catch((error)=&gt; {
          console.log(error);
  
          if (error.status === 400) {
            return Observable.throw(new Error(error.status));
          } else if (error.status === 401) {
            return Observable.throw(new Error(error.status));
          } else if (error.status === 403) {
            return Observable.throw(new Error(error.status));
          } else if (error.status === 404) {
            return Observable.throw(new Error(error.status));
          } else if (error.status === 420) {
            return Observable.throw(new Error(error.status));
          } else {
            return Observable.throw(new Error(error.status));
          }
        });
    }
  </code></pre>