Minimal KISS implementation of TimeAgo.

timeago.js

const SECOND = 1000;
const MINUTE = 60*SECOND;
const HOUR = 60*MINUTE;
const DAY = 24*HOUR;
const WEEK = 7*DAY;
const MONTH = 30*DAY;
const YEAR = 52*WEEK;

function timeAgo(date) {
  const diff =  Date.now() - new Date(date).getTime();
  if (!diff || diff < 0) return 'some time ago';
  if (diff < 1.5*MINUTE) return `a moment ago`;
  if (diff < 1.5*HOUR) return Math.round(diff/MINUTE) + ' minutes ago';
  if (diff < 1.5*DAY) return Math.round(diff/HOUR) + ' hours ago';
  if (diff < 1.5*WEEK) return Math.round(diff/DAY) + ' days ago';
  if (diff < 1.5*MONTH) return Math.round(diff/WEEK) + ' weeks ago';
  if (diff < 1.5*YEAR) return Math.round(diff/MONTH) + ' months ago';
  return Math.round(diff/YEAR) + ' years ago';
}

Sometimes the aim is to keep the implementation extremely simple, over trying to find the most complete and perfect solution for a problem.

This algorithm for time ago formatting (ie 10 minutes ago) is such an example. It deals with 80% and ignores 20% of use cases for the sake of brevity.

This worse is better approach is easier to understand, copy, extend and to port to other frameworks and languages.