code: function countNumMatches(contents, queryExpr) {
      if (!contents) {
          return 0;
      }
      var matches = contents.match(queryExpr);
      return matches ? matches.length : 0;
  }
docs: Counts the number of matches matching the queryExpr in the given contents
  @param   {String} contents  The contents to search on
  @param   {Object} queryExpr
  @return {number} number of matches