loginService

import { Injectable, Input, SimpleChanges } from '@angular/core';
import { FacebookService, LoginResponse, InitParams, LoginOptions, LoginStatus } from 'ngx-facebook';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';

@Injectable()

export class LoginService {

    private connectionOn = new BehaviorSubject<boolean>(false);
    connectionOn$ = this.connectionOn.asObservable();
    @Input() logResponse: LoginResponse;

    constructor(private fb: FacebookService) {


        let initParams: InitParams = {
            // access data
        };

        fb.init(initParams);

    }

    private set isConnected(value: boolean) {
        this.connectionOn.next(value);
    }

    private get isConnected():boolean{
        return this.connectionOn.getValue();
    }

    login() {

        const loginOptions: LoginOptions = {
            enable_profile_selector: true,
            return_scopes: true,
            scope: 'public_profile,user_likes,email,pages_show_list'
        };

        this.fb.login()
            .then((response: LoginResponse) => this.logResponse = response)
            .catch((error: any) => console.error(error));
    }

    ngOnChanges(changes: SimpleChanges) {
        if (this.logResponse.status === 'connected') {
            this.isConnected(true);
        } else {
            this.isConnected(false);
        }
    }
}