$re = '/export type \w+ =(?: (\S+))?(?:\s+\| (\S+))*;/ms';
$str = 'export type RegistrationMode = "Closed" | "RequireApplication" | "Open";
export type SearchType =
| "All"
| "Comments"
| "Posts"
| "Communities"
| "Users"
| "Url";';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php