color.js

var tty = require('tty');

var styles = {
  'bold':      ['\033[1m', '\033[22m'],
  'italic':    ['\033[3m', '\033[23m'],
  'underline': ['\033[4m', '\033[24m'],
  'inverse':   ['\033[7m', '\033[27m'],
  'black':     ['\033[30m', '\033[39m'],
  'red':       ['\033[31m', '\033[39m'],
  'green':     ['\033[32m', '\033[39m'],
  'yellow':    ['\033[33m', '\033[39m'],
  'blue':      ['\033[34m', '\033[39m'],
  'magenta':   ['\033[35m', '\033[39m'],
  'cyan':      ['\033[36m', '\033[39m'],
  'white':     ['\033[37m', '\033[39m'],
  'default':   ['\033[39m', '\033[39m'],
  'grey':      ['\033[90m', '\033[39m'],
  'bgBlack':   ['\033[40m', '\033[49m'],
  'bgRed':     ['\033[41m', '\033[49m'],
  'bgGreen':   ['\033[42m', '\033[49m'],
  'bgYellow':  ['\033[43m', '\033[49m'],
  'bgBlue':    ['\033[44m', '\033[49m'],
  'bgMagenta': ['\033[45m', '\033[49m'],
  'bgCyan':    ['\033[46m', '\033[49m'],
  'bgWhite':   ['\033[47m', '\033[49m'],
  'bgDefault': ['\033[49m', '\033[49m']
}

var enabled = !process.env.NOCOLOR && tty.isatty(1) && tty.isatty(2);

Object.keys(styles).forEach(function(style) {
  Object.defineProperty(String.prototype, style, {
    get: function() { return (enabled ? styles[style][0] + this + styles[style][1] : this); },
    enumerable: false
  });
});