ckeditor in Drupal 8 custom module - ckeditor

Question

I am currently developing a custom module for Drupal 8.
While adding a backend form to get some data from users I tried to get the ckeditor configured to replace my textareas... and failed >.<
here is the form definition:
$form['text'] = array(
'#type' => 'textarea',
'#title' => t('Text'),
'#required' => TRUE,
'#attributes' => array(
'id' => 'text',
'style' => 'max-width: 650px'
),
'#default_value' => $data['text']
);
where do I need to load the ckeditor to replace my textarea?
things I already tried:
$build['#attached'] = array(
'js' => array(
drupal_get_path('module', 'ckeditor') . '/js/ckeditor.js'
drupal_render($build);
and
drupal_load_library("ckeditor", "ckeditor");
but I can't load all the dependencies

Answer 1

Refer to the Drupal 8 form API which has a text_format form type. A check on your #default_value is also recommended.
Navigate to Configuration > Content authoring > Text formats and editors giving you an overview of the current available text formats. The ones listed here can be used in the #format proprty of your form field. (Default fallback currently is basic_html)
Try to change your code to:
$form['text'] = array(
'#type' => 'text_format',
'#title' => t('Text'),
'#required' => TRUE,
'#default_value' => isset($data['text']) ? $data['text'] : '',
'#format' => 'full_html',
);

Answer 2

I had a similar issue but had issues saving the data with above solution. In the end it looked like this:
$form['body'] = [
'#type' => 'text_format',
'#title' => $this->t('Body'),
'#description' => $this->t('Message'),
'#default_value' => $config->get('body'),
'#format' => 'full_html',
];
and in submitForm method I save config like so
/**
* {#inheritdoc}
*/
public function submitForm(array &$form, FormStateInterface $form_state) {
parent::submitForm($form, $form_state);
$this->config('my_module.default')
->set('body', $form_state->getValue('body')['value'])
->save();
}
Note the reference to the attached ['value'] array.