JavaScript: Plural - create a plural or singluar sentence based on a number

Plural.js

/*
  Plural - create singlular or plural sentence based on number given (all numbers but 1 return plural sentence)
	
	var str = "Do you want to delete this? There {are|is} [num] book{s} attached."
	
	var num = 2 // or 0, 3, 4, ...
		"Do you want to delete this? There are 2 books attached."
	
	var num = 1
		"Do you want to delete this? There is 1 book attached."
*/
plural: function(str, num){

	var indx = num == 1 ? 1 : 0;
	
	str = str.replace(/\[num\]/, num);
	
	str = str.replace(/{(.[^}]*)}/g, function(wholematch,firstmatch){
		
		var values = firstmatch.split('|');
		
		return values[indx] || '';
	});
	
	return str;
}

Plural.php

/*
    PHP Port of Plural.js
*/
public static function plural($str, $num){
    
	$indx = $num == 1 ? 1 : 0;
	
	$str = preg_replace("/\[num\]/", $num, $str);
	
	$str = preg_replace_callback("/{(.[^}]*)}/", function($matches) use($indx){
		
		$values = explode('|', $matches[1]);
		
		return isset($values[$indx]) ? $values[$indx] : '';
	}, $str);
	
	return $str;
}