finding the word at a position in javascript

Question

For string input of \'this is a sentence\' it must return \'is\' when position is 6 or 7. When position is 0, 1, 2, 3 or 4 result must be \'this\'.

What is the easie

Answer 1

function getWordAt(str, pos) {

   // Sanitise input
   str = str + "";
   pos = parseInt(pos, 10);

   // Snap to a word on the left
   if (str[pos] == " ") {
      pos = pos - 1;
   }

   // Handle exceptional cases
   if (pos < 0 || pos >= str.length-1 || str[pos] == " ") {
      return "";
   }

   // Build word
   var acc = "";
   for ( ; pos > 0 && str[pos-1] != " "; pos--) {}
   for ( ; pos < str.length && str[pos] != " "; pos++) {
      acc += str[pos];
   }

   return acc;
}

alert(getWordAt("this is a sentence", 6));

Something like this. Be sure to thoroughly test the loop logic; I didn't.