Calling function SocialLoginModule, function calls are not supported.Consider replacing the function or lambda with a reference

after "ng serve" or "npm start" i'm getting below error,

after saving any file from work space, it compiles all project files and this time it works well. I'm not getting why this happens. Could you please someone help me to get out of this. Please find below image for the same.

Please find below app.module.ts file

    import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';
import { RouterModule } from '@angular/router';
import { SocialLoginModule, AuthServiceConfig, GoogleLoginProvider, FacebookLoginProvider } from "angular4-social-login";
import { StarRatingModule } from 'angular-star-rating';
import { AppComponent } from './app.component';
import { LandingPageComponent } from './landing-page/landing-page.component';
import { AppHeaderComponent } from './app-header/app-header.component';
let config = new AuthServiceConfig([
  {
    id: GoogleLoginProvider.PROVIDER_ID,
    provider: new GoogleLoginProvider("")
  },
  {
    id: FacebookLoginProvider.PROVIDER_ID,
    provider: new FacebookLoginProvider("")
  }
]);
export function provideConfig() {
  return config;
}
@NgModule({
  declarations: [
    AppComponent,
    LandingPageComponent,
    AppHeaderComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    StarRatingModule.forRoot(),
    RouterModule.forRoot([
      { path: 'landing', component: LandingPageComponent },
      { path: '', redirectTo: 'landing', pathMatch: 'full' }
    ]),
    SocialLoginModule.initialize(config)
  ],
  providers: [{
    provide: AuthServiceConfig,
    useFactory: provideConfig
  }],
  bootstrap: [AppComponent]
})
export class AppModule { }