Get a humanized, "Morning", "Afternoon", "Evening" from moment.js **Great for user greetings!**

momentjs.humanized.triplesplit.time.js

function getGreetingTime (m) {
	var g = null; //return g
	
	if(!m || !m.isValid()) { return; } //if we can't find a valid or filled moment, we return.
	
	var split_afternoon = 12 //24hr time to split the afternoon
	var split_evening = 17 //24hr time to split the evening
	var currentHour = parseFloat(m.format("HH"));
	
	if(currentHour >= split_afternoon && currentHour <= split_evening) {
		g = "afternoon";
	} else if(currentHour >= split_evening) {
		g = "evening";
	} else {
		g = "morning";
	}
	
	return g;
}

/* USE
    //The var "humanizedGreeting" below will equal (assuming the time is 8pm) "Good evening, James."
    
    var user = "James";
    var humanizedGreeting = "Good " + getGreetingTime(moment()) + ", " + user + ".";
*/

To anyone finding this from Google like I did, I set mine up like this:

const currentHour = new Date().getHours();

const greetingMessage =
  currentHour >= 4 && currentHour < 12 ? // after 4:00AM and before 12:00PM
  'Good morning.' :
  currentHour >= 12 && currentHour <= 17 ? // after 12:00PM and before 6:00pm
  'Good afternoon.' :
  currentHour > 17 || currentHour < 4 ? // after 5:59pm or before 4:00AM (to accommodate night owls)
  'Good evening.' : // if for some reason the calculation didn't work
  'Welcome'

console.log(greetingMessage)

Because I think people looking at their computer or phone between 12AM and 4AM are more likely staying up late than waking up early 😉

Fair enough, but let's just shift midnight by 4 hours, and simplify the expressions.

let currentHour = new Date().getHours();
if (currentHour < 4) {  // After midnight, but before 4am
  currentHour = currentHour + 24
}

const greetingMessage =
  currentHour < 12 ? // after 4:00AM and before 12:00PM
  'Good morning.' :
  currentHour < 18 ? // after 12:00PM and before 6:00pm
  'Good afternoon.' :
  currentHour < 28 ? // // after 5:59pm or before 4:00AM (to accommodate night owls)
  'Good evening.' : // if for some reason the calculation didn't work
  'Welcome'