Integration with COI

Integration with COI is simple.

For any form field representing a configuration value, add the full config-object+key to the element. See #config key in example:

$site_config = $this->config('system.site');
$form['site_information']['site_slogan'] = [
  '#type' => 'textfield',
  '#title' => t('Slogan'),
  '#default_value' => $site_config->get('slogan'),
  '#description' => t("How this is used depends on your site's theme."),
  '#config' => [
    'key' => 'system.site:slogan',
  ],
];

Where the key is the config object, then colon symbol (":"), then config key.

Your module does not need to depend on COI. If COI becomes installed and enabled, your field will automatically receive new functionality.

Secrets

If your field represents a secret, such as passwords, authorization tokens, etc, add the secret key.

$site_config = $this->config('system.site');
$form['site_information']['site_slogan'] = [
  '#type' => 'textfield',
  '#title' => t('Slogan'),
  '#default_value' => $site_config->get('slogan'),
  '#description' => t("How this is used depends on your site's theme."),
  '#config' => [
    'key' => 'system.site:slogan',
    'secret' => TRUE,
  ],
];

The secret key accepts boolean values TRUE or FALSE. If not set, COI assumes FALSE.