Programmatically load 'add content' form for custom content type in form or block plugin

Question

I understand that users could use 'add content' from the admin menu, but I'm building a custom block plugin or form so the add content form can be displayed in a block on the page instead of requiring users to use an actual admin page. I've done this before by manually creating forms in a render array in a form plugin that save the field values into a node upon form submit, but it'd nice to actually be able to just grab the actual add node form and render it directly.

In my research I found code to do this for Drupal 7

module_load_include('inc', 'node', 'node.pages');
$node_form = new stdClass;
$node_form->type = 'yourContentType';
$node_form->language = LANGUAGE_NONE;
$form = drupal_get_form('yourContentType_node_form', $node_form);
return $form;

But I need a way to do this in Drupal 8. I've loaded custom form controllers before like so

$content = \Drupal::formBuilder()->getForm('Drupal\my_module\Form\MyForm');

But I'm not sure how I would add a specific 'add content' form. How would I get the form of any 'add content' for a specific content type?

UPDATE: I found a path to something called 'NodeForm' and I tried to use it like so

$content = \Drupal::formBuilder()->getForm('Drupal\node\NodeForm\publication');

Where publication was a content type I wanted to load the form for. But I receive an error

The form argument Drupal\node\NodeForm\publication is not a valid form

And out of curiosity I tried

$content = \Drupal::formBuilder()->getForm('Drupal\node\NodeForm');

But that gives me the error

Fatal error: Call to a member function getEntityTypeId() on null in /Library/WebServer/Documents/aaep/web/core/lib/Drupal/Core/Entity/EntityForm.php on line 77

Answer 1

Entity forms are built by EntityFormBuilder::getForm(). The parameter is an entity not a form class. This can be an existing entity or a new entity to add content.

For example to add content for the content type article you create this entity:

$node = \Drupal\node\Entity\Node::create(['type' => 'article']);

Use the new entity to build the form:

$form = \Drupal::service('entity.form_builder')->getForm($node);