multistep skip steps based off of users' input

Thank you for the response, if you have the time - could you talk me through how you would approach such a solution?

My thought process is the following:

1. Use form alter hook to identify number of partners
2. Add logic to save / submit that checks if the user needs to see next partner questions
3. based off of two, route them to the right step

One part I haven't been able to track down, is how are you handling the routing for multistep? Can you point me to where this is in the code or the docs?

Also, if you think this approach isn't worth it, that would be great to know.

Thanks!

Great I'll look into it. Yea, after my last post, I decided the best route was to go with states AP so I have already moved it over.

Thanks again for the prompt replies. I really love this module and plan on contributing when I get some bandwidth.

So here is another way I handled this, but it works better with the following use case. Say you have a ten step form and after step four a user doesn't qualify to continue. You want to track those that don't qualify which requires saving the submission to the DB; this is the approach I used.

Once I realized that the submit button (which saves to DB) was available via form alter, I toggled the access value for both the submit and next buttons. The user(s) that don't qualify to continue will only see the submit button, while the user(s) that do, will see the next button.

$form['actions']['submit']['#access'] = TRUE;
$form['actions']['next']['#access'] = FALSE;

Finally, if you don't need to save the submission when they 'disqualify', you can always redirect the response to a node:

$does_not_qualify = new RedirectResponse('/node/1'); 
$does_not_qualify->send();

Right now this is not possible using just hook_form_alter() because the wizard's pages have been completely initialized when hook_form_alter() is called.

Well that might not be necessary because we can update wizard['current_page'] via the form_alter hook. I guess this can be described as spoofing what page the form_state is coming from but for now, it accomplishes what I need.

//find step
$wizard = $form_state->get('wizard');
$current_step = $wizard['current'];

//steps that can 'jump' to step_4_key
$step3_p1_q18 = array_search('step3_p1_q18', $wizard['pages']);
$step3_p2_q18 = array_search('step3_p2_q18', $wizard['pages']);
$step3_p3_q18 = array_search('step3_p3_q18', $wizard['pages']);
$step3_p4_q18 = array_search('step3_p4_q18', $wizard['pages']);

//skip destination
$step_4_key = array_search('step_4_std', $wizard['pages']);

//skip criteria
if (($current_step == $step3_p1_q18 && $partner_count == 1) ||
  ($current_step == $step3_p2_q18 && $partner_count == 2) ||
  ($current_step == $step3_p3_q18 && $partner_count == 3) ||
  ($current_step == $step3_p4_q18 && $partner_count == 4))  {
  // in the backend, this will be incremented by one
  $skip_to = $step_4_key - 1;
  $wizard['current'] = $skip_to;
  $form_state->set('wizard', $wizard);
}

@jrockowitz great, can you provide a quick example of how I should do it now?

Just wanted to follow up with this. I was able to achieve this with the following code.

function goto_step($goto_step, $pages, \Drupal\Core\Form\FormStateInterface $form_state){
  //have a key as a string
  $all_keys = array_keys($pages);
  $goto_step_key = array_search($goto_step, $all_keys);
  if($goto_step_key > 0){
    //the backend pointer for page will add 1 so to go our page we must -1
    $form_state->set('current_page', $all_keys[$goto_step_key-1]);
  }
  else{
    //something went wrong
  }
}

@jrockowitz awesome. Done deal take a look #2850813: How to programmatically skip pages in wizard forms.