WordPress at a glance
function is not described

WP_Theme::get_template_directory_uri() public WP 3.4.0

Returns the URL to the directory of a theme's "template" files.

In the case of a child theme, this is the URL to the directory of the parent theme's files.

{} It's a method of the class: WP_Theme{}

No Hooks.

Return

String. URL to the template directory.

Usage

$WP_Theme = new WP_Theme();
$WP_Theme->get_template_directory_uri();

Changelog

Since 3.4.0 Introduced.

Code of WP_Theme::get_template_directory_uri() WP 5.5.1

<?php
public function get_template_directory_uri() {
	if ( $this->parent() ) {
		$theme_root_uri = $this->parent()->get_theme_root_uri();
	} else {
		$theme_root_uri = $this->get_theme_root_uri();
	}

	return $theme_root_uri . '/' . str_replace( '%2F', '/', rawurlencode( $this->template ) );
}