new date() today to epoch code example

Example 1: javascript today date in epoch

const start = Date.now(); 
/*gives the number of milliseconds elapsed since January 1, 1970 00:00:00 UTC.*/

Example 2: epoch

Epoch timestamp is a unit of measurement for time. It is the number of
seconds elapsed since the countdown has started. 

Beginning epochs per system:
macOS - January 1, 1904
Windows - January 1, 1601
Unix - January 1, 1970