I'm following this tutorial: https://www.tutorialesprogramacionya.com/angularya/detalleconcepto.php?punto=89&codigo=89&inicio=80. and it has the following part of code:

import { Component } from '@angular/core';
import { FormGroup, FormControl } from '@angular/forms';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  conversion!: string;
  potenciaNumero!: number;
  cantidad!: number;

  formularioConversion = new FormGroup({
    numerodecimal: new FormControl(''),
    base: new FormControl('octal'),
    potencia: new FormControl('2'),
    largo: new FormControl(true)
  });

  submit() {
    if (this.formularioConversion.value.base == "hexadecimal")
      this.conversion = parseInt(this.formularioConversion.value.numerodecimal).toString(16);
    if (this.formularioConversion.value.base == "octal")
      this.conversion = parseInt(this.formularioConversion.value.numerodecimal).toString(8);
    this.potenciaNumero = Math.pow(parseInt(this.formularioConversion.value.numerodecimal?), parseInt(this.formularioConversion.value.potencia));
    if (this.formularioConversion.value.largo)
      this.cantidad = this.formularioConversion.value.numerodecimal.length;
  }
}

the problem is that in the submit function i have the variable "numerodecimal" that is defined as an object but threated as a string. How can i solve this error?