auto refresh in ionic 4 code example

Example: ionic refresh

<!-- Custom Refresher Properties -->
<ion-content>
  <ion-refresher slot="fixed" pullFactor="0.5" pullMin="100" pullMax="200">
    <ion-refresher-content></ion-refresher-content>
  </ion-refresher>
</ion-content>

import { Component } from '@angular/core';

@Component({
  selector: 'refresher-example',
  templateUrl: 'refresher-example.html',
  styleUrls: ['./refresher-example.css'],
})
export class RefresherExample {
  constructor() {}

  doRefresh(event) {
    console.log('Begin async operation');

    setTimeout(() => {
      console.log('Async operation has ended');
      event.target.complete();
    }, 2000);
  }
}