MSAL service wrapper from https://github.com/Azure-Samples/active-directory-b2c-javascript-msal-singlepageapp/issues/9#issuecomment-347556074

msal.service.ts

import { Injectable } from '@angular/core';
import { AppConfig } from '../app.config';
import {UserAgentApplication} from 'msal';
@Injectable()
export class MsalService {
    accessToken: string;
    userAgentApplication: UserAgentApplication = null;

    constructor() {
        this.userAgentApplication = new UserAgentApplication(
            AppConfig.tenantConfig.clientID,
            AppConfig.tenantConfig.signInSignUp,
            this._onTokenCallback

        )
     }
     signIn(): void {
        const clientApp = this.userAgentApplication;
        const tenantConfig = AppConfig.tenantConfig;
        clientApp.loginRedirect(tenantConfig.b2cScopes);
     }
     signOut(): void {
        this.userAgentApplication.logout();
     }
     isAuthenticated(): boolean{
        return this.userAgentApplication.getUser() != null;
     }

     getToken(){}

     private _onTokenCallback = (errorDesc: any, token: any, error: any, tokenType: any) => {
        if (token) {
            this.accessToken = token;
          }
          if (errorDesc) {
            if (errorDesc.indexOf('AADB2C90118') > -1) {
              //  forgot
              console.log(errorDesc);
              this.userAgentApplication = new UserAgentApplication(
                AppConfig.tenantConfig.clientID,
                AppConfig.tenantConfig.passwordReset,
                this._onTokenCallback
              );
              this.signIn();
            }
          }
     }
}