JavaScript Code for handling colors in texts printed on console. Using ANSI color codes.

text_colors.js

const ESC         = '\x1B';
const RESET       = ESC + '[0m';
const BOLD        = ESC + '[1m';
const BOLDRESET   = ESC + '[22m';

const CLRSCR = ESC + '[2J';
const CUR00  = ESC + '[H'
const CLS    = CLRSCR + CUR00;

const fgCIdx = idx => ESC + `[38;5;${idx}m`;
const bgCIdx = idx => ESC + `[48;5;${idx}m`;

String.prototype.fgCIdx = function (clrIdx) {
  return fgCIdx(clrIdx) + this + RESET;
}

String.prototype.bgCIdx = function (clrIdx) {
  return bgCIdx(clrIdx) + this + RESET;
}

String.prototype.bold = function () {
  return BOLD + this + BOLDRESET;
}

String.prototype.colors = function (fgIdx, bgIdx = null) {
  let retString = "";
  if (null != fgIdx) retString = ESC + fgCIdx(fgIdx);
  if (null != bgIdx) retString += ESC + bgCIdx(bgIdx);
  
  return retString + this + RESET;
}

Example color table: