ActionScript 3.0: String Utility Methods (trim, startsWith, endsWith etc.)

public class StringUtils 
{
 
 public function StringUtils() 
 {
  
 }
 
 public static function concatAsString(array:Array):String {
  var ret:String = "";
  for each(var str:String in array) {
   ret += str;
  }
  return ret;
 }

 public static function concatAllAsString(delimita:String, ...strs):String {
  if (strs == null || strs.length == 0) {
   return "";
  }
  var ret:String = "";
  for each(var str:String in strs) {
   ret += delimita + str
  }
  return ret.substr(1, ret.length - 1);
 }
   
 public static function trim(src:String):String {
  return src.replace(/^[\s\t]+(.+)[\s\t]+$/, "$1");
 }
 
 public static function endsWith(str:String, seacrh:String):Boolean {
  return str.length > seacrh.length && 
      str.substr(seacrh.length-1, seacrh.length) === seacrh;
 }
 
 public static function startsWith(prefix:String, testStr:String):Boolean
 {
  return testStr.length >= prefix.length && testStr.substr(0, prefix.length) === prefix;
 }
}