Allows registering Backbone templates as scripts

register-template.php

/**
 * @author Franz Josef Kaiser http://unserkaiser.com/
 * @link http://chat.stackexchange.com/transcript/message/19439060#19439060
 */

// Allows registering Backbone templates as scripts
// Add type="text/template" and id="{handle}" for Backbones .tmpl <script>s
add_filter( 'script_loader_tag', function( $html, $handle, $src )
{
	$dom = new \DOMDocument;
	$dom->loadHTML( $html );

	/** @var \DOMElement $tag */
	foreach ( $dom->getElementsByTagName( 'script' ) as $tag )
	{
		if (
			! empty( $src )
			and $tag->hasAttribute( 'type' )
			and strstr( $src, '.tmpl' )
			)
		{
			$tag->setAttribute( 'type', 'text/template' );
			$tag->setAttribute( 'id', $handle );
			$tag->nodeValue = file_get_contents( $src );
			$tag->removeAttribute( 'src' );
			$html = $dom->saveHTML( $tag );
		}
	}

	return $html;
}, 10, 3 );