node/lib/internal/http.js

'use strict';

const { setUnrefTimeout } = require('internal/timers');

var nowCache;
var utcCache;

function nowDate() {
  if (!nowCache) cache();
  return nowCache;
}

function utcDate() {
  if (!utcCache) cache();
  return utcCache;
}

function cache() {
  const d = new Date();
  nowCache = d.valueOf();
  utcCache = d.toUTCString();
  setUnrefTimeout(resetCache, 1000 - d.getMilliseconds());
}

function resetCache() {
  nowCache = undefined;
  utcCache = undefined;
}

function ondrain() {
  if (this._httpMessage) this._httpMessage.emit('drain');
}

module.exports = {
  outHeadersKey: Symbol('outHeadersKey'),
  ondrain,
  nowDate,
  utcDate
};