nested routes of a custom outlet which use parent's template

custom_outlet_nested_routes.ts

// route definition
route = {
  path:       '',
  component:  CustomLayoutComponent,
  outlet:     'custom',
  children: [{
    path:       'child-route',
    component:  ChildComponent
  }]
}

// parent layout component 
import { Component, OnInit } from '@angular/core';

@Component({
  template: `<router-outlet></router-outlet>`
})
export class CustomLayoutComponent implements OnInit {
  constructor() { }

  ngOnInit() {
  }
}