JWT refresh token in Angular 6 Interceptor with Ngrx

http-jwt-interceptor.ts

import { Injectable } from '@angular/core';
import {
    HttpRequest,
    HttpHandler,
    HttpEvent,
    HttpInterceptor
} from '@angular/common/http';
import { Observable, BehaviorSubject } from 'rxjs';
import { filter, take, switchMap } from 'rxjs/operators';
import { SigninModuleState } from '../../signin/store/models/signin.model';
import { Store } from '@ngrx/store';
import { SIGNIN_STORE } from '../../signin/store/reducer/signin.reducer';
import * as SigninActions from '../../signin/store/actions/signin.actions';

import { JWTUtil } from '../../shared/utils/jwt-util';

@Injectable()
export class HttpJwtInterceptor implements HttpInterceptor {

    private jwtToken: any = {
        accessToken: "",
        refreshToken: ""
    }

    private refreshTokenInProgress = false;

    private refreshTokenSubject: BehaviorSubject<any> = new BehaviorSubject<any>(
        null
    );

    constructor(private store: Store<SigninModuleState>, private jwtUtil: JWTUtil) {
        this.store
            .select(SIGNIN_STORE)
            .subscribe((data: SigninModuleState) => {
                console.log(data)
                if (this.jwtToken.accessToken == "" || this.jwtToken.accessToken != this.getAccessToken(data)) {
                    this.jwtToken.accessToken = this.getAccessToken(data);
                    this.jwtToken.refreshToken = this.getRefreshToken(data);
                    this.refreshTokenSubject.next(this.jwtToken.refreshToken);
                }
            })
    }

    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

        console.log("PRE INTERCEPT: ", request.url);

        if (request.url.includes("api/signin") || request.url.includes("api/token/refresh")) {
            console.log("Login or refresh API!")
            console.log("POST INTERCEPT: ", request.url);
            return next.handle(request);
        }

        this.refreshTokenInProgress = this.isRefreshTokenInProgress(this.jwtToken.accessToken);

        if (this.refreshTokenInProgress) {
            // If refreshTokenInProgress is true, we will wait until refreshTokenSubject has a non-null value
            // – which means the new token is ready and we can retry the request again
            console.log("Return Refresh Token In Progress!")
            return this.refreshTokenSubject.pipe(
                filter(result => result !== null),
                take(1),
                switchMap(() => next.handle(this.addAuthenticationToken(request)))
            );
        } else {
            console.log("In else block. Setting refreshTokenSubject to null!")
            // Set the refreshTokenSubject to null so that subsequent API calls will wait until the new token has been retrieved
            this.refreshTokenSubject.next(null);
            return next.handle(this.addAuthenticationToken(request));
        }
    }

    private getAccessToken(data: SigninModuleState): string {
        if (data && data.loginContext) {
            return data.loginContext.accessToken;
        } else {
            return "NOT_AVAILABLE";
        }
    }

    private getRefreshToken(data: SigninModuleState): string {
        if (data && data.loginContext) {
            return data.loginContext.refreshToken;
        } else {
            return "NOT_AVAILABLE";
        }
    }

    addAuthenticationToken(request: HttpRequest<any>) {
        // Get access token from Local Storage
        const accessToken = this.jwtToken.accessToken;

        // If access token is null this means that user is not logged in
        // And we return the original request
        if (!accessToken) {
            console.log("Token not found!")
            return request;
        }

        // We clone the request, because the original request is immutable
        console.log("Returning cloned request with bearer token!")
        let newRequest = request.clone({
            setHeaders: {
                Authorization: "Bearer " + accessToken
            }
        });
        console.log("POST INTERCEPT: ", newRequest.url);
        return newRequest;
    }

    isRefreshTokenInProgress(accessToken: string) {
        if (this.jwtUtil.isExpired(accessToken)) {
            console.log("Token expire. Dispatching new token action!")
            // Set the refreshTokenSubject to null so that subsequent API calls will wait until the new token has been retrieved
            this.refreshTokenSubject.next(null);
            this.store.dispatch(new SigninActions.RefreshToken(this.jwtToken));
            return true;
        }
        else {
            return false;
        }
    }

}