Add Logic with THEMENAME.theme for Drupal 8, Drupal 9

Last updated July 27, 2016

Every theme can contain an optional THEMENAME.theme file. This file contains additional business logic written in PHP and is primarily used for manipulation of the variables available for a template file, and suggesting alternative candidate template file names.

In this tutorial we'll learn:

  • The use-case for THEMENAME.theme files
  • Where to find them
  • When you might need to edit one