Events in Ionic v4 - ionic-framework

Question

I'm using Ioni v4Beta and I'm traying to update the sidemenu when the user is login.
I search but the usual solution is use Events:
Ionic 3 refresh side menu after login
https://ionicframework.com/docs/api/util/Events/
But in the new version I don't find it, and I don't know how to do it
https://beta.ionicframework.com/docs/api

Answer 1

Thanks a lot, but I finally find how to import it:
import { Events } from '#ionic/angular';

Answer 2

Example on how to do it with subjects:
export const someEvent:Subject = new Subject();
export class ReceivingClass implements OnDestroy, OnInit
{
private someEventSubscription:Subscription;
public OnInit():void{
someEventSubscription = someEvent.subscribe((data) => console.log(data);
}
public onDestroy():void{
someEvent.unsubscribe();
}
}
export class SendingClass implements OnInit
{
public OnInit():void{
setTimeout(() => {
someEvent.next('hi');
}, 500);
}
}

Answer 3

Are you aware that Ionic v4 events will be deprecated soon?
I was also trying to update the sidemenu when a user logs in as well, so i tried using: import { Events } from '#ionic/angular';
However I got a warning referring me to this link https://angular.io/guide/observables#basic-usage-and-terms which I failed to follow because am not that familiar with observables.
After much research I found that I can still use events but I had to import them from angular's router directive.
This was my code before:
/* import was */
import { Events } from '#ionic/angular';
import { Storage } from '#ionic/storage';//ignore this import if doesn't apply to your code
/* inside the class */
constructor(
private events: Events,
private storage: Storage
) {
this.events.subscribe("updateMenu", () => {
this.storage.ready().then(() => {
this.storage.get("userLoginInfo").then((userData) => {
if (userData != null) {
console.log("User logged in.");
let user = userData.user;
console.log(user);
}
else {
console.log("No user found.");
let user = {};
}
}).catch((error)=>{
console.log(error);
});
}).catch((error)=>{
console.log(error);
});
});
}
changes i made that actually got my code working and deprecation warning gone:
/* import is now */
import { Router,RouterEvent } from '#angular/router';
import { Storage } from '#ionic/storage';//ignore this import if it does't apply to your code
Rest of code
constructor(
public router: Router,
public storage: Storage
){
this.router.events.subscribe((event: RouterEvent) => {
this.storage.ready().then(() => {
this.storage.get("userLoginInfo").then((userData) => {
if (userData != null) {
/*console.log("User logged in.");*/
let user = userData.user;
/*console.log(this.user);*/
}
else {
/*console.log("No user found.");*/
let user = {};
}
}).catch((error)=>{
console.log(error);
});
}).catch((error)=>{
console.log(error);
});
});
}
I got the idea after seeing this https://meumobi.github.io/ionic/2018/11/13/side-menu-tabs-login-page-ionic4.html. I hope my answer can be useful.

Answer 4

Steps to resolve the issue
import events in login page and in sidemenu view
In login page, after login success do your logic to publish the events.
for eg:
this.authService.doLogin(payload).subscribe((response) => {
if (response.status) {
this.storage.set('IS_LOGGED_IN', true);
this.events.publish('user:login');
}
}, (error) => {
console.log(error);
});
In sidemenu view, create a listener to watch the events 'user:login'
for eg:
this.menus = [];
// subscribe events
this.events.subscribe('user:login', () => {
// DO YOUR LOGIC TO SET THE SIDE MENU
this.setSidemenu();
});
// check whether the user is logged in or not
checkIsUserloggedIn() {
let isLoggedIn = false;
if (this.storage.get('IS_LOGGED_IN') == '' ||
this.storage.get('IS_LOGGED_IN') == null ||
this.storage.get('IS_LOGGED_IN') == undefined) {
isLoggedIn = false;
} else {
isLoggedIn = true;
}
return isLoggedIn;
}
// to set your sidemenus
setSidemenu() {
let isUserLoggedIn = this.checkIsUserloggedIn();
if(isUserLoggedIn) {
this.menus = ['Home', 'Aboutus', 'Contactus', 'My Profile', 'Logout'];
} else {
this.menus = ['Login', 'Home', 'Aboutus', 'Contactus'];
}
}