WordPress: Can you programmatically create page templates?

Question

I am currently building a React/Redux theme for WordPress using the WordPress API. I need to add Page Templates to my theme. I can do this by creating almost empty files like:

<?php
/* Template Name: My Template */
?>

But I would like to create these 'Page Templates' programmatically.

The functionality I required is to be able to select a 'Page Template' inside the WordPress CMS and have this come down on the API. This functions as expected if the 'Page Templates' are created as above.

Is this possible?

Answer 1

This can be achieved using the theme_page_templates filter.

CONST CUSTOM_PAGE_TEMPLATES = array(
  array('slug' => 'home', 'label' => 'Home'),
  array('slug' => 'content-page', 'label' => 'Content Page'),
  array('slug' => 'ordering', 'label' => 'Ordering'),
  array('slug' => 'reviews', 'label' => 'Reviews')
); 

/**
 * Add file-less page templates to the page template dropdown 
 */
add_filter('theme_page_templates', function($page_templates, $wp_theme, $post) {
  foreach(CUSTOM_PAGE_TEMPLATES as $template) {
    // Append if it doesn't already exists
    if (!isset($page_templates[$template['slug']])) {
      $page_templates[$template['slug']] = $template['label'];
    }
  }
  return $page_templates;
}, PHP_INT_MAX, 3);