ngx-admin/src/app/pages/layout/stepper/stepper.component.ts

import { Component, OnInit } from '@angular/core';
import { UntypedFormBuilder, UntypedFormGroup, Validators } from '@angular/forms';

@Component({
  selector: 'ngx-stepper',
  templateUrl: 'stepper.component.html',
  styleUrls: ['stepper.component.scss'],
})
export class StepperComponent implements OnInit {

  firstForm: UntypedFormGroup;
  secondForm: UntypedFormGroup;
  thirdForm: UntypedFormGroup;

  constructor(private fb: UntypedFormBuilder) {
  }

  ngOnInit() {
    this.firstForm = this.fb.group({
      firstCtrl: ['', Validators.required],
    });

    this.secondForm = this.fb.group({
      secondCtrl: ['', Validators.required],
    });

    this.thirdForm = this.fb.group({
      thirdCtrl: ['', Validators.required],
    });
  }

  onFirstSubmit() {
    this.firstForm.markAsDirty();
  }

  onSecondSubmit() {
    this.secondForm.markAsDirty();
  }

  onThirdSubmit() {
    this.thirdForm.markAsDirty();
  }
}