src/community/helpers/formatTimeAgo.ts

// https://blog.webdevsimplified.com/2020-07/relative-time-format/
const formatter = new Intl.RelativeTimeFormat(undefined, {
  numeric: "auto",
})

const DIVISIONS = [
  { amount: 60, name: "seconds" },
  { amount: 60, name: "minutes" },
  { amount: 24, name: "hours" },
  { amount: 7, name: "days" },
  { amount: 4.34524, name: "weeks" },
  { amount: 12, name: "months" },
  { amount: Number.POSITIVE_INFINITY, name: "years" },
] as const

export function formatTimeAgo(date: Date): string {
  let duration = (date.getTime() - Date.now()) / 1000

  for (let i = 0; i <= DIVISIONS.length; i++) {
    const division = DIVISIONS[i]
    if (Math.abs(duration) < division.amount) {
      return formatter.format(Math.round(duration), division.name)
    }
    duration /= division.amount
  }
  throw new Error("")
}