How to dynamically feed the this.validations_form?

[rapropos]

interface Customer {
  id: string;
  name: string;
}

customersToFormGroup(fb: FormBuilder, customers: Customer[]): FormGroup {
  let ctrls = {};
  for (let c of customers) {
    for (let liquid of ["water", "wine"]) {
      ctrls[`amount${liquid}_amt${c.id}`] = new FormControl("", Validators.required);
    }
  }
  return fb.group(ctrls);
}