time-ago.js

const MONTH_NAMES = [
  'Janeiro', 'Fevereiro', 'Março', 'Abril', 'Maio', 'Junho',
  'Julho', 'Agosto', 'Setembro', 'Outubro', 'Novembro', 'Dezembro',
];


function getFormattedDate(date, prefomattedDate = false, hideYear = false) {
  const day = date.getDate();
  const month = MONTH_NAMES[date.getMonth()];
  const year = date.getFullYear();
  const hours = date.getHours();
  let minutes = date.getMinutes();

  if (minutes < 10) {
    // Adding leading zero to minutes
    minutes = `0${minutes}`;
  }

  if (prefomattedDate) {
    // Today at 10:20
    // Yesterday at 10:20
    return `${prefomattedDate} às ${hours}:${minutes}`;
  }

  if (hideYear) {
    // 10. January at 10:20
    return `${day}. ${month} às ${hours}:${minutes}`;
  }

  // 10. January 2017. at 10:20
  return `${day}. ${month} ${year}. às ${hours}:${minutes}`;
}


// --- Main function
function timeAgo(dateParam) {
  if (!dateParam) {
    return null;
  }

  const date = typeof dateParam === 'object' ? dateParam : new Date(dateParam);
  const DAY_IN_MS = 86400000; // 24 * 60 * 60 * 1000
  const today = new Date();
  const yesterday = new Date(today - DAY_IN_MS);
  const seconds = Math.round((today - date) / 1000);
  const minutes = Math.round(seconds / 60);
  const isToday = today.toDateString() === date.toDateString();
  const isYesterday = yesterday.toDateString() === date.toDateString();
  const isThisYear = today.getFullYear() === date.getFullYear();


  if (seconds < 5) {
    return 'agora';
  } if (seconds < 60) {
    return `${seconds} segundos atrás`;
  } if (seconds < 90) {
    return 'cerca de um minuto atrás';
  } if (minutes < 60) {
    return `${minutes} minutos atrás`;
  } if (isToday) {
    return getFormattedDate(date, 'Hoje'); // Today at 10:20
  } if (isYesterday) {
    return getFormattedDate(date, 'Ontem'); // Yesterday at 10:20
  } if (isThisYear) {
    return getFormattedDate(date, false, true); // 10. January at 10:20
  }

  return getFormattedDate(date); // 10. January 2017. at 10:20
}