Angular 14 - typed forms

app.component.ts

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

@Component({
  selector: 'profile',
  templateUrl: './profile.component.html',
  styleUrls: ['./profile.component.css'],
})
export class ProfileComponent {
  profileForm = new FormGroup({
    firstName: new FormControl('Mark'),
    lastName: new FormControl('Doe'),
  });

  populate() {
    // TS error: Argument of type '10' is not assignable to parameter of type 'string | null'.
    this.profileForm.controls.firstName.setValue(10);
  }
}