Issue type

• bug report
• feature request

Issue description

Current behavior:
Components are re-rendering for unnecessary reasons. For example when I scroll the page, or hover menu items, ... components are re-rendering HTML.

Expected behavior:
Re-render components just when needed.

Steps to reproduce:
Use the following code with ngx-admin starter-kit:

Related code:
dashboard.component.ts:

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

@Component({
  selector: 'ngx-dashboard',
  templateUrl: './dashboard.component.html',
})
export class DashboardComponent {
  constructor() {}

  checkUpdate() {
    console.log('component is re-rendering!!!');
    return 1;
  }
}

dashboard.component.html

<div class="row">
  <nb-card>
    <nb-card-body>Hello from ngx-admin sandbox project.</nb-card-body>
  </nb-card>
  <div style="width: 200px; height: 1000px; background-color: yellow">
    <br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
    {{checkUpdate()}}
    <br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
  </div>
</div>