node_modules/tap-mocha-reporter/lib/browser/tty.js

exports.isatty = function(){
  return true;
};

exports.getWindowSize = function(){
  if ('innerHeight' in global) {
    return [global.innerHeight, global.innerWidth];
  } else {
    // In a Web Worker, the DOM Window is not available.
    return [640, 480];
  }
};