truncate a word at a word break. optimized for naturally occurring word breaks. with optional length argument.

truncateAtWord.js

truncateAtWord = function(str){
  var tail = "...",
      len = arguments[1] || 10;
  if(str.length <= len){
    return str;
  }
  if(str.charAt(len) === " "){
    return str.slice(0,len)+tail;
  }
   return str.slice(0,len).split(" ").slice(0,-1).join(" ")+tail;
};