mailpoet_email_editor_send_preview_email filter-hookWC 1.0

Usage

add_filter( 'mailpoet_email_editor_send_preview_email', 'wp_kama_mailpoet_email_editor_send_preview_filter' );

/**
 * Function for `mailpoet_email_editor_send_preview_email` filter-hook.
 * 
 * @param  $data 
 *
 * @return 
 */
function wp_kama_mailpoet_email_editor_send_preview_filter( $data ){

	// filter...
	return $data;
}
$data
-

Where the hook is called

Email_Api_Controller::send_preview_email_data()
mailpoet_email_editor_send_preview_email
woocommerce/packages/email-editor/src/Engine/class-email-api-controller.php 74
$result = apply_filters( 'mailpoet_email_editor_send_preview_email', $data );

Where the hook is used in WooCommerce

woocommerce/packages/email-editor/src/Engine/class-email-editor.php 99
add_filter( 'mailpoet_email_editor_send_preview_email', array( $this->send_preview_email, 'send_preview_email' ), 11, 1 ); // allow for other filter methods to take precedent.