Get file size for Image Picker

Ionic Native
1

It is necessary to get the file size by the native url.
The value in the message is displayed, but it is not possible to assign it to a variable.
Here is my code:

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';
import { ImagePicker } from '@ionic-native/image-picker';
import { File } from '@ionic-native/file';
@Component({
	selector: 'page-home',
	templateUrl: 'home.html'
})
export class HomePage {

	public images = [];
	public sizes = [];
	
	constructor(
		public navCtrl: NavController,
		private imagePicker: ImagePicker,
		private file: File
	) { }

	openPicker() {
		var options = {
			quality: 100,
			outputType: 0
		};
		this.imagePicker.getPictures(options).then((results) => {
			for(let i=0; i < results.length; i++) {
				this.images.push({'url': results[i],  'size': '???'});
				this.file.resolveLocalFilesystemUrl(results[i]).then((fileEntry) => {
					this.getFileSize(fileEntry);
				});
			}
			setTimeout(() => { 
				console.log(this.sizes); /* Empty Array !!!!!!!!!!!!!!!!!!! */
			}, 1000);
		});
	}

	getFileSize(fileEntry) {
		fileEntry.file(function(file) {
			alert(file.size); /* Show and work */
			this.sizes.push(file.size); /* NOT WORK */
		});
	}

}

That’s what I really need, but it causes a mistake.
I did not find the documentation of “fileEntry.file” for ionic 2/3

this.imagePicker.getPictures(options).then((results) => {
	for(let i=0; i < results.length; i++) {
		this.file.resolveLocalFilesystemUrl(results[i]).then((fileEntry) => {
			fileEntry.file(function(file) { /* <--------- I did not find the documentation of "fileEntry.file" for ionic 2/3 */
				this.images.push({'url': results[i], 'size': file.size});
			});
		});
	}
});

Thankful in advance for the help.