javascript - How to wait for a function to finish its execution in angular 2.? -

below code, want login() , authenticated() functions wait getprofile() function finish execution. tried several ways promise etc. couldn't implement it. please suggest me solution.

import { injectable }      '@angular/core'; import { tokennotexpired } 'angular2-jwt'; import { myconfig }        './auth.config';  // avoid name not found warnings declare var auth0lock: any;  @injectable() export class auth {   // configure auth0   lock = new auth0lock(myconfig.clientid, myconfig.domain, {     additionalsignupfields: [{       name: "address",                              // required       placeholder: "enter address",            // required       icon: "https://example.com/address_icon.png", // optional       validator: function(value) {                  // optional         // accept addresses more 10 chars         return value.length > 10;       }     }]   });    //store profile object in auth class   userprofile: any;    constructor() {     this.getprofile();  //i want here function finish work   }     getprofile() {     // set userprofile attribute if saved profile     this.userprofile = json.parse(localstorage.getitem('profile'));      // add callback lock `authenticated` event     this.lock.on("authenticated", (authresult) => {       localstorage.setitem('id_token', authresult.idtoken);        // fetch profile information       this.lock.getprofile(authresult.idtoken, (error, profile) => {         if (error) {           // handle error           alert(error);           return;         }          profile.user_metadata = profile.user_metadata || {};         localstorage.setitem('profile', json.stringify(profile));         this.userprofile = profile;       });     });   };    public login() {     this.lock.show();     this.getprofile();  //i want here function finish work   };    public authenticated() {     this.getprofile();  //i want here function finish work     return tokennotexpired();   };    public logout() {     // remove token , profile localstorage     localstorage.removeitem('id_token');     localstorage.removeitem('profile');     this.userprofile = undefined;   }; } 

like saw in comments, have use promise or observable achieve this, since behaviour pretty simple, should use promise because observable have lot of features don't need in case.

here promise version of service:

import { injectable }      '@angular/core'; import { tokennotexpired } 'angular2-jwt'; import { myconfig }        './auth.config';  // avoid name not found warnings declare var auth0lock: any;  @injectable() export class auth {   // configure auth0   lock = new auth0lock(myconfig.clientid, myconfig.domain, {     additionalsignupfields: [{       name: "address",                              // required       placeholder: "enter address",            // required       icon: "https://example.com/address_icon.png", // optional       validator: function(value) {                  // optional         // accept addresses more 10 chars         return value.length > 10;       }     }]   });  //store profile object in auth class userprofile: any;  constructor() {     this.getprofile();  //i want here function finish work   }   getprofile():promise<void> {     return new promise<void>(resolve => {     // set userprofile attribute if saved profile     this.userprofile = json.parse(localstorage.getitem('profile'));      // add callback lock `authenticated` event     this.lock.on("authenticated", (authresult) => {       localstorage.setitem('id_token', authresult.idtoken);        // fetch profile information       this.lock.getprofile(authresult.idtoken, (error, profile) => {         if (error) {           // handle error           alert(error);           return;         }          profile.user_metadata = profile.user_metadata || {};         localstorage.setitem('profile', json.stringify(profile));         this.userprofile = profile;         resolve()       });     });    }) };  public login(): promise<void>{     this.lock.show();     return this.getprofile();  //i want here function finish work   };    public authenticated():void{     this.getprofile().then( () => {           return tokennotexpired();     });   };    public logout():void {     // remove token , profile localstorage     localstorage.removeitem('id_token');     localstorage.removeitem('profile');     this.userprofile = undefined;   }; } 

more on promise here