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

Plural.js

/**
* naive implementation of singular/plural sentence based on count.
* e.g.:
* var str = "Do you want to delete this? There {are|is} [num] book{s} attached."
*
* pluralize(str, 1); // => Do you want to delete this? There is 1 book attached."
* pluralize(str, 2); // => "Do you want to delete this? There are 2 books attached."
*
* @method function
*
* @param  {String} str  sentence with {} and []
* @param  {Number} count
*
* @return {String}
*/
pluralize: function(str, count) {
  var indx = count === 1 ? 1 : 0;
  var result;

  result = str.replace(/\[count\]/, count);

  result = result.replace(/{(.[^}]*)}/g, function(wholematch, firstmatch) {
    return firstmatch.split('|')[indx] || '';
  });

  return result;
}