$ npm install ngx-device-detector --save

  import { Component } from '@angular/core';
  ...
  import { DeviceDetectorService } from 'ngx-device-detector';
  ...
  @Component({
    selector: 'home',  // <home></home>
    styleUrls: [ './home.component.scss' ],
    templateUrl: './home.component.html',
    ...
  })

  export class HomeComponent {
    deviceInfo = null;
    ...
    constructor(..., private http: Http, private deviceService: DeviceDetectorService) {
      this.epicFunction();
    }
    ...
    epicFunction() {
      console.log('hello `Home` component');
      this.deviceInfo = this.deviceService.getDeviceInfo();
      const isMobile = this.deviceService.isMobile();
      const isTablet = this.deviceService.isTablet();
      const isDesktopDevice = this.deviceService.isDesktop();
      console.log(this.deviceInfo);
      console.log(isMobile);  // returns if the device is a mobile device (android / iPhone / windows-phone etc)
      console.log(isTablet);  // returns if the device us a tablet (iPad etc)
      console.log(isDesktopDevice); // returns if the app is running on a Desktop browser.
    }
    ...
  }

import { InjectionToken } from '@angular/core';
import { Request, Response } from 'express';

export const REQUEST = new InjectionToken<Request>('REQUEST');
export const RESPONSE = new InjectionToken<Response>('RESPONSE');

import { Inject, Injectable, Optional, PLATFORM_ID } from '@angular/core';
import { REQUEST } from 'path/to/express.tokens';
import { Request } from 'express';
import { DeviceDetectorService } from 'ngx-device-detector';
import { isPlatformServer } from '@angular/common';

@Injectable()
export class UniversalDeviceDetectorService extends DeviceDetectorService {
  constructor(@Inject(PLATFORM_ID) platformId: any, @Optional() @Inject(REQUEST) request: Request) {
    super(platformId);
    if (isPlatformServer(platformId)) {
      super.setDeviceInfo((request.headers['user-agent'] as string) || '');
    }
  }
}

{
  provide: DeviceDetectorService,
  useClass: UniversalDeviceDetectorService
},

  $ npm run tsc

  $ npm run lint

  $ npm run test

  $ npm run build

  $ npm install -g @angular/cli

  $ cd demo
  $ npm install
  $ ng serve