Random date in JavaScript

randomDate.js

function randomDate(start, end) {
  return new Date(start.getTime() + Math.random() * (end.getTime() - start.getTime()))
}

console.log(randomDate(new Date(2012, 0, 1), new Date()))

@DidarHalla I am not a JS dev but I think that it works like this:

• start.getTime() - you get the number of milliseconds since January 1, 1970 00:00:00 UTC for the start
• Math.random() - you get a floating-point number greater than or equal to 0 and less than 1
• end.GetTime() - you get the number of milliseconds since January 1, 1970 00:00:00 UTC for the end

Then this is the order of actions:

1. You get the number of miliseconds between end and start dates.
2. You multiply the result by Math.random()
3. You add the result to the number of miliseconds from the start.getTime(). The result of this operation can be the same as start.getTime() (if Math.random() is zero) but it cannot be greater than end.getTime() because you multiply the difference by Math.random that is less than 1.
   (I do not know if it can be equal end.getTime() because I do not know the "scale" of roundings)
4. You use the result as the parameter for "new Date(our result)" constructor that accepts number of milliseconds since January 1, 1970 00:00:00 UTC and uses it to create the date object.

Btw. I know that your comment is almost 2 years old but maybe it will be useful for someone else or for you if you gave up the topic :D