How to use Callback function on successful HTTP request in Angular2

Question

I am new to Angular2. I have referred the Hero Tutorial given in official web site and have written the following code for HTTP post request in Angular2 as per my requirement. I am used to java-script and i use AJAX calls to interact with web server, in javascript-AJAX call we can perform some function on successful AJAX call(callback function). How do i achieve that in angular2 ? i want to use Alerts also. On success/fail of each call show a Alert Box saying its Success or Failure.

@Injectable()
export class LicenceService {
constructor(private http: Http) {}
private headers = new Headers({'Content-Type': 'application/json'});
/* URL to web api*/
private licenceUrl = 'http://localhost:5000/***/****/installation/uploadLicense';  



sendData(key: string){
    return this.http
        .post(this.licenceUrl, key, this.headers)
        .toPromise()
        .then(res => res.json().data)
        .catch(this.handleError);
}
private static handleError (error: any) {
    console.log(error);
    return Promise.reject(error.json());
}

Answer 1

All you need is already in your code

sendData(key: string){
    return this.http
        .post(this.licenceUrl, key, this.headers)
        .toPromise()
        .then(res => {
           res.json().data;
           // code here is executed on success
         })
        .catch(this.handleError);
}

or for the caller

this.sendData(somekey).then(result => /*put after after success code here */);