WordPress theme file locator and loader.

class-file.php

<?php
/**
 * File Class
 *
 * Helper class to locate and load files in child/parent
 * theme only if they exist.
 *
 * Rename "Themeslug" according to your needs.
 * Edit according to your needs...
 */
class Themeslug_File {

	/**
	 * Locate file by its relative path.
	 *
	 * Searches child theme first, before falling back to parent theme.
	 * If the file is not found, returns an empty string.
	 *
	 * @param  string $path_relative
	 */
	public static function get_path( $path_relative = '' ) {
		$path_absolute = get_theme_file_path( $path_relative );

		if ( ! file_exists( $path_absolute ) ) {
			$path_absolute = '';
		}

		return $path_absolute;
	}

	/**
	 * Load a file using different PHP statements.
	 *
	 * @param  string $path_relative
	 * @param  string $statement
	 */
	public static function load( $path_relative = '', $statement = 'require' ) {
		$path = self::get_path( $path_relative );

		if ( ! empty( $path ) ) {
			switch ( $statement ) {
				case 'require':
					require $path;
					break;

				case 'require_once':
					require_once $path;
					break;

				case 'include':
					include $path;
					break;

				case 'include_once':
					include_once $path;
					break;

				default:
					break;
			}
		}
	}

}

WordPress theme file locator and loader

Rename Themeslug according to your needs (your WordPress theme slug).
Edit & share according to your needs...

How to use

Copy the file into your theme and load it in functions.php file with require get_template_directory() . '/class-file.php'; (or require get_template_directory() . '/path/to/class-file.php';).

To find the child/parent theme file path use Themeslug_File::get_path( 'relative/path/to/file.php' );. If the file does not exist, empty string is returned.

To load a child/parent theme file use Themeslug_File::load( 'relative/path/to/file.php', 'require' );. If the file does not exist, nothing is loaded. The require argument is the default value, so it can be committed, or replaced with require_once or include or include_once depending on your needs.