simple string format utilities

string-format.js

/*
 * Fair License (Fair)
 *
 * Copyright (c) 2012, IWAMURO Motonori
 * 
 * Usage of the works is permitted provided that this instrument is
 * retained with the works, so that any entity that uses the works is
 * notified of this instrument.
 * 
 * DISCLAIMER: THE WORKS ARE WITHOUT WARRANTY.
 */

function comma(n) {
  var s = String(n).split(".", 2);
  var i = s[0].replace(/\B(?=(?:\d{3})+$)/g, ",");
  return s.length == 1 ? i : i + "." + s[1];
}

function repeat(s, cnt) {
  var r = "";
  for (; cnt > 0; --cnt)
    r += s;
  return r;
}

function alignRight(s, col, pad) {
  s = String(s);
  // U+00A0 is NBSP.
  return repeat(pad || "\u00a0", col - s.length) + s;
}