Error: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: '[object Object]'. Current value: '2'.

Sometimes I catching an exception:

LoadingBarComponent.html:2 ERROR Error: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: '[object Object]'. Current value: '2'.
    at viewDebugError (core.es5.js:8433)
    at expressionChangedAfterItHasBeenCheckedError (core.es5.js:8411)
    at checkBindingNoChanges (core.es5.js:8575)
    at checkNoChangesNodeInline (core.es5.js:12416)
    at checkNoChangesNode (core.es5.js:12390)
    at debugCheckNoChangesNode (core.es5.js:13183)
    at debugCheckDirectivesFn (core.es5.js:13085)
    at Object.eval [as updateDirectives] (LoadingBarComponent.html:2)
    at Object.debugUpdateDirectives [as updateDirectives] (core.es5.js:13067)
    at checkNoChangesView (core.es5.js:12230)

  | View_LoadingBarComponent_0 | @ | LoadingBarComponent.html:2
-- | -- | -- | --
  | proxyClass | @ | compiler.es5.js:14985
  | webpackJsonp.../../../core/@angular/core.es5.js.DebugContext_.logError | @ | core.es5.js:13407
  | webpackJsonp.../../../core/@angular/core.es5.js.ErrorHandler.handleError | @ | core.es5.js:1080
  | (anonymous) | @ | core.es5.js:4819
  | webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invoke | @ | zone.js:392
  | webpackJsonp.../../../../zone.js/dist/zone.js.Zone.run | @ | zone.js:142
  | webpackJsonp.../../../core/@angular/core.es5.js.NgZone.runOutsideAngular | @ | core.es5.js:3844
  | webpackJsonp.../../../core/@angular/core.es5.js.ApplicationRef_.tick | @ | core.es5.js:4819
  | (anonymous) | @ | core.es5.js:4684
  | webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invoke | @ | zone.js:392
  | onInvoke | @ | core.es5.js:3890
  | webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invoke | @ | zone.js:391
  | webpackJsonp.../../../../zone.js/dist/zone.js.Zone.run | @ | zone.js:142
  | webpackJsonp.../../../core/@angular/core.es5.js.NgZone.run | @ | core.es5.js:3821
  | next | @ | core.es5.js:4684
  | schedulerFn | @ | core.es5.js:3635
  | webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.SafeSubscriber.__tryOrUnsub | @ | Subscriber.js:239
  | webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.SafeSubscriber.next | @ | Subscriber.js:186
  | webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.Subscriber._next | @ | Subscriber.js:127
  | webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.Subscriber.next | @ | Subscriber.js:91
  | webpackJsonp.../../../../rxjs/_esm5/Subject.js.Subject.next | @ | Subject.js:56
  | webpackJsonp.../../../core/@angular/core.es5.js.EventEmitter.emit | @ | core.es5.js:3621
  | checkStable | @ | core.es5.js:3855
  | onLeave | @ | core.es5.js:3934
  | onInvokeTask | @ | core.es5.js:3884
  | webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invokeTask | @ | zone.js:424
  | webpackJsonp.../../../../zone.js/dist/zone.js.Zone.runTask | @ | zone.js:192
  | webpackJsonp.../../../../zone.js/dist/zone.js.ZoneTask.invokeTask | @ | zone.js:499
  | invokeTask | @ | zone.js:1540
  | globalZoneAwareCallback | @ | zone.js:1566

My code

[package.json]
...
"dependencies": {
...
  "@ngx-loading-bar/http": "^1.0.0-alpha.16",
...

[app/app.module.ts]
// node_modules
import {BrowserModule} from '@angular/platform-browser';
import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
import {NgModule} from '@angular/core';
import {HttpModule} from '@angular/http';
import {Routes, RouterModule} from '@angular/router';
import {NgbModalModule} from '@ng-bootstrap/ng-bootstrap';
import { LoadingBarHttpModule } from '@ngx-loading-bar/http';
// AppComponent
import {AppComponent} from './app.component';

// Core
import {CoreModule} from './core/core.module';

// Features
import {LoginModule, ActivationModule, MainModule} from './features';

// Setup routes
const appRoutes: Routes = [
    {path: '**', redirectTo: '/'},
];

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        BrowserAnimationsModule,
        HttpModule,
        LoadingBarHttpModule,
        RouterModule.forRoot(appRoutes),
        NgbModalModule.forRoot(),
        CoreModule,
        LoginModule,
        ActivationModule,
        MainModule
    ],
    bootstrap: [AppComponent]
})
export class AppModule {
}

[app/app.component.html]
<ngx-loading-bar></ngx-loading-bar>
<router-outlet></router-outlet>

[aitboudad]

that’s great, I’m working on a fix right now!

[KSANTHOSHKUMA]

@aitboudad , your explanation is awesome, i am getting the same error, now it is solved with your explantation . VERY GREAT EXPLANATION FROM YOU , your knowledge is in very peak stage