Angular Material Stepper component prevent going to all the non visited steps

I had this issue and trying to solve it i've stumbled upon this post. My goal was to block the next step (formGroup) before the users at least had some input on the fields. So I came up with this simple solution:

HTML (notice I have a mix between ngBoostrap and Angular Material, no harm done, I hope :)

<div class="container-fluid ">
    <div class="row" style="height: 100vh">
        <div class="col-md-6">
               
            <mat-vertical-stepper [linear]="namesGroup.invalid" #stepper>
                <mat-step [stepControl]="namesGroup" >
                    <form [formGroup]="namesGroup">
                        <ng-template matStepLabel>Fill out your name and username</ng-template>
                        <mat-form-field>
                            <mat-label>Name</mat-label>
                            <input matInput placeholder="First name" formControlName="name" required>
                        </mat-form-field>
                        <!--Errors-->
                        <div *ngIf="name.touched && name.invalid">
                            <mat-error *ngIf="name.errors.required"><small>Name is required</small></mat-error>
                        </div>
                        <!--Errors-->
                        <mat-form-field>
                            <mat-label>Username</mat-label>
                            <input matInput placeholder="Username" formControlName="username" required>
                        </mat-form-field>
                        <!--Errors-->
                        <div *ngIf="username.touched && username.invalid">
                            <mat-error *ngIf="username.errors.required"><small> Username is required</small></mat-error>
                        </div>
                        <!--Errors-->
                        <div>
                            <button [disabled]="namesGroup.invalid" mat-raised-button color="primary" matStepperNext>Next</button>
                        </div>
                    </form>

I have two more form groups and the logic repeats itself. So im just binding the [linear] atribute to the valid/invalid state of the form. And it works like a charm. I hope I have contributed. Cheers

Check this link . You need to use linear stepper.

A stepper marked as linear requires the user to complete previous steps before proceeding. For each step, the stepControl attribute can be set to the top level AbstractControl that is used to check the validity of the step.

Example shown as below

    import { Component, Input } from '@angular/core';
    import {FormBuilder, FormGroup, Validators} from '@angular/forms';
    import {MatIconRegistry} from '@angular/material';
    
    @Component({
      selector: 'stepper',
      templateUrl: './stepper.component.html'
    })
        export class StepperComponent  {
           isLinear = true;
          firstFormGroup: FormGroup;
          secondFormGroup: FormGroup;
        
          constructor(private _formBuilder: FormBuilder){
        
          }
           ngOnInit() {
            this.firstFormGroup = this._formBuilder.group({
              firstCtrl: ['', Validators.required]
            });
            this.secondFormGroup = this._formBuilder.group({
              secondCtrl: ['', Validators.required]
            });
          }
        }

and html is

    <mat-vertical-stepper [linear]="isLinear">
      <mat-step [stepControl]="firstFormGroup">
        <form [formGroup]="firstFormGroup">
          <ng-template matStepLabel>Fill out your name</ng-template>
          <mat-form-field>
            <input matInput placeholder="Last name, First name" formControlName="firstCtrl" required>
          </mat-form-field>
          <div>
            <button mat-button mat-raised-button color="primary" matStepperNext>Next</button>
          </div>
        </form>
      </mat-step>
      <mat-step [stepControl]="secondFormGroup">
        <form [formGroup]="secondFormGroup">
          <ng-template matStepLabel>Fill out your address</ng-template>
          <mat-form-field>
            <input matInput placeholder="Address" formControlName="secondCtrl" required>
          </mat-form-field>
          <div>
            <button mat-button mat-raised-button color="primary" matStepperPrevious>Back</button>
            <button mat-button mat-raised-button color="primary" matStepperNext>Next</button>
          </div>
        </form>
      </mat-step>
      <mat-step>
        <ng-template matStepLabel icon>Done</ng-template>
        You are now done.
        <div>
          <button mat-button mat-raised-button color="primary" matStepperPrevious>Back</button>
        </div>
      </mat-step>
    </mat-vertical-stepper>

The solution that I found to this problem is to use completed attribute of step. Refer to the line of code given below:

<mat-step [completed]="isCompleted">

When isCompleted is true it will enable the next step.

Note: For this to work, the stepper component must be in the linear mode. This can be done by setting the attribute linear on the stepper component, like

<mat-horizontal-stepper linear>