Posting another script solution DateX (author)
for anyone interested
DateX does NOT wrap the original Date object, but instead offers an identical interface with additional methods to format, localise, parse, diff and validate dates easily. So one can just do new DateX(..) instead of new Date(..) or use the lib as date utilities or even as wrapper or replacement around Date class.
const str = (new Date()).toISOString().slice(0, 19).replace(/-/g, "/").replace("T", " ");
It uses the built-in function Date.toISOString(), chops off the ms, replaces the hyphens with slashes, and replaces the T with a space to go from say '2019-01-05T09:01:07.123' to '2019/01/05 09:01:07'.
Local time instead of UTC
const now = new Date();
const offsetMs = now.getTimezoneOffset() * 60 * 1000;
const dateLocal = new Date(now.getTime() - offsetMs);
const str = dateLocal.toISOString().slice(0, 19).replace(/-/g, "/").replace("T", " ");