Relative time ago

timeAgo.ts

function timeAgo(time: number, now = Date.now()) {
  const is = (interval: number, cycle: number) =>
    cycle >= interval ? Math.round(cycle / interval) : 0

  const secs = (now - time) / 1000
  const mins = is(60, secs)
  const hours = is(60, mins)
  const days = is(24, hours)
  const weeks = is(7, days)
  const months = is(30, days)
  const years = is(12, months)

  let amt = years
  let cycle = "year"

  if (secs <= 1) {
    return "just now"
  } else if (years > 0) {
    amt = years
    cycle = "year"
  } else if (months > 0) {
    amt = months
    cycle = "month"
  } else if (weeks > 0) {
    amt = weeks
    cycle = "week"
  } else if (days > 0) {
    amt = days
    cycle = "day"
  } else if (hours > 0) {
    amt = hours
    cycle = "hour"
  } else if (mins > 0) {
    amt = mins
    cycle = "minute"
  } else if (secs > 0) {
    amt = secs
    cycle = "second"
  }

  const v = Math.round(amt)

  return `${v === 1 ? (amt === hours ? "an" : "a") : v} ${cycle}${v > 1 ? "s" : ""} ago`
}