CODEWITHSUNDEEP
javascriptangulartypescriptionic2
dkmostafa
dkmostafa

Reputation: 35

nav inside a promise function in ionic 2

I am using ionic2 in a new application , and i want to route my page inside a promise function that calls a http request from a server,

I want to access the Navcontroller inside a promise function , but the Navcontroller is not accessible from inside the promise function. the promise function is a promise of a function inside the AuthenticationService
this is my code inside app.component.ts :

 import {Component, ViewChild, Inject} from '@angular/core';
    import {Platform, NavController} from 'ionic-angular';
    import { StatusBar } from 'ionic-native';
    import { HomePage } from '../pages/home/home';
    import { LoginPage } from '../pages/login/login';
    import {Authentication} from '../providers/authentication';

    @Component({
      template: `<ion-nav #myNav [root]="rootPage"></ion-nav>`,
        providers:[Authentication],
    })

    export class MyApp {


        @ViewChild('myNav') public nav : NavController

      //rootPage = LoginPage;

      constructor(platform: Platform, private auth:Authentication) {
        platform.ready().then(() => {
          StatusBar.styleDefault();
        });

      }

        ngOnInit() {


            this.auth.index()
                .then(function (data) {
                    if(data['flag']==1)
                    {
                        this.nav.setRoot(HomePage);
                    }
                    else
                    {
                        this.nav.setRoot(LoginPage);
                    }

                })

and this is the error : 

EXCEPTION: Uncaught (in promise): TypeError: Cannot read property 'nav' of null    
TypeError: Cannot read property 'nav' of null.

Upvotes: 2

Views: 574

Answers (1)

eko
eko

Reputation: 40647

Change

.then(function (data) {

to 

.then( (data) => {

If you use function instead of the fat arrow syntax, your this won't be refering to the page.

I'd recommend you to read: https://stackoverflow.com/a/20279485/5706293

Upvotes: 2

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