Apple JXA script to create and populate an album with a random sample of favorite photos

Make AppleTV Screensaver.applescript.js

#!/usr/bin/osascript -l JavaScript
// Apple JXA script to create and populate an album with a random sample of favorite photos
// Author: @n8henrie
// Rename from .applescript.js to .applescript (.js for GitHub syntax highlighting)

// https://stackoverflow.com/a/11935263/1588795
function getRandomSubarray(arr, size) {
    var shuffled = arr.slice(0), i = arr.length, temp, index;
    while (i--) {
        index = Math.floor((i + 1) * Math.random());
        temp = shuffled[index];
        shuffled[index] = shuffled[i];
        shuffled[i] = temp;
    }
    return shuffled.slice(0, size);
}

function main() {
	const Photos = new Application("Photos")
	Photos.includeStandardAdditions = true

	const millisInYear = (1000 * 60 * 60 * 24 * 365)
	const today = new Date()

	// Oversample starting with
	const startDate = new Date(today - millisInYear * 1.5)

	const albumLength = 100
	// Ratio that should be since startDate
	const newItemRatio = 0.5
	const newLength = Math.floor(albumLength * newItemRatio)

	var atvAlbum = Photos.albums().find(album => album.name() == "Apple TV Screensaver")
	if (atvAlbum !== undefined) {
		Photos.delete(atvAlbum)
	}
	atvAlbum = Photos.make({new: "album", named: "Apple TV Screensaver"})

	var favorites = Photos.favoritesAlbum().mediaItems().filter(item => {
		return (
			!/.mov$/i.test(item.filename()) &&
			!/.avi$/i.test(item.filename())
		)
	})

	var newFavs = favorites.filter(item => item.date() >= startDate)
	var oldFavs = favorites.filter(item => item.date() < startDate)

	var newSample = getRandomSubarray(newFavs, newLength)
	var oldSample = getRandomSubarray(oldFavs, albumLength - newSample.length)
	Photos.add(newSample, {to: atvAlbum})
	Photos.add(oldSample, {to: atvAlbum})

}
main()