renderer1.ts

import { Component } from '@angular/core';
import { ViewChild } from "@angular/core/src/metadata/di";

@Component({
  selector: 'app-root',
  templateUrl: '<input type="text" #input>'
})
export class AppComponent {
  @ViewChild("input") input;
  
  ngAfterContentInit() {
    this.input.nativeElement.focus();
  }
}