File Transfer Error for ngx

When I install file transfer I can not use it without the “/ ngx” and when I import it it throws me an error, here my code

import {Component} from '@angular/core';
import {IonicPage, LoadingController, NavController, NavParams} from 'ionic-angular';
import {MemesProvider} from "../../providers/memes/memes";
import {NuevoComentarioPage} from "../nuevo-comentario/nuevo-comentario";
import {FileTransfer} from "@ionic-native/file-transfer/ngx";
import { File } from '@ionic-native/file/ngx';
/**
 * Generated class for the VerMemePage page.
 *
 * See https://ionicframework.com/docs/components/#navigation for more info on
 * Ionic pages and navigation.
 */


@IonicPage()
@Component({
  selector: 'page-ver-meme',
  templateUrl: 'ver-meme.html',
})
export class VerMemePage {
  id: any;
  ruta:any= "";
  meme: any = {
    titulo: "",
    promedio: "",
    descripcion: "",
    ruta: ""
  };
  comentarios = [];

  constructor(public navCtrl: NavController, public navParams: NavParams, private memeProv: MemesProvider,
              private loadingCtrl: LoadingController,private transfer:FileTransfer, private file: File) {
    this.id = this.navParams.get('id');
  }

  ionViewDidEnter() {
    this.getMeme();
  }

//TODO ngif para evitar comentarios del creador
  getMeme() {
    const loader = this.loadingCtrl.create({
      content: "Cargando meme..."
    });
    loader.present();
    this.memeProv.verMeme(this.id).subscribe((result) => {
      this.meme = result;
      this.ruta = "https://memeappapi.herokuapp.com/memes/" + result.ruta;
      this.meme.ruta = result.ruta;
      loader.dismiss();
    });
    const loadera = this.loadingCtrl.create({
      content: "Cargando comentarios..."
    });
    loadera.present();
    this.memeProv.comentariosM(this.id).subscribe((result) => {
      this.comentarios = result.comentarios;
      loadera.dismiss();
    })
  }

  descargar(ruta) {
    const fileTransfer: FileTransferObject = this.transfer.create();
    /*fileTransfer.download(this.ruta, this.file.dataDirectory + ruta + '.png').then((entry) => {
      console.log('download complete: ' + entry.toURL());
    }, (error) => {
      // handle error
    });*/
  }

  nuevo() {
    this.navCtrl.push(NuevoComentarioPage, {
      id: this.id
    });
  }
}

and my info system

Ionic:

ionic (Ionic CLI) : 4.4.0 (C:\Users\obedn\AppData\Roaming\npm\node_modules\ionic)
Ionic Framework : ionic-angular 3.9.5
@ionic/app-scripts : 3.2.3

Cordova:

cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
Cordova Platforms : android 7.1.4
Cordova Plugins : cordova-plugin-ionic-keyboard 2.1.3, (and 6 other plugins)

System:

NodeJS : v10.15.3 (C:\Program Files\nodejs\node.exe)
npm : 6.4.1
OS : Windows 10
The error is

ERROR TypeError: Cannot read property ‘constructor’ of undefined

Same issue, any solution?

You shouldn’t be using the FileTransfer plugin any more anyway. It’s been obsolete for years. Just use ordinary HttpClient.