strSubString

strSubString(
  const string,     // source string
  const start,      // starting position, index based 1
  [const count,     // # of characters
   const padchar])  // padding character

Extracts a substring from a string. If count is ommitted, all remaining characters are taken.

Examples:

const s = 'hello world';
strSubString(s,2,2);         // el
strSubString(s,4);           // lo world
strSubString(s,1,20,'*');    // hello world*********
strSubString('',1,20,'-');   // --------------------