client/lib/media-serialization/strategies/string.js
function parseAsShortcode( node, _parsed ) {
	// Attempt to convert string element into DOM node. If successful, recurse
	// to trigger the shortcode strategy
	const shortcode = parse( node );
	if ( shortcode ) {
		return _recurse( shortcode, _parsed );
	}

	return _parsed;
}
function parseAsShortcode( node, _parsed ) {
	// Attempt to convert string element into DOM node. If successful, recurse
	// to trigger the shortcode strategy
	const shortcode = parse( node );
	if ( shortcode ) {
		return _recurse( shortcode, _parsed );
	}

	return _parsed;
}
Given a media string, attempts to parse as a shortcode and returns an
object containing all detected values.

@param  {string} node    Media object to parse
@param  {Object} _parsed In recursion, the known values
@return {Object}         Object of all detected values