Moment.js twitter-style fromNow

moment.js

assert(typeof moment == 'function', 'moment dependency')

function gt (input, key) {
  var dur = moment.duration(input, key)
  return this.as('milliseconds') > dur.as('milliseconds')
}

function lt (input, key) {
  var dur = moment.duration(input, key)
  return this.as('milliseconds') < dur.as('milliseconds')
}

_.extend(moment.duration.fn, { gt: gt, lt: lt })

function fromNowTwitter () {
  var ms = moment().diff(this)
  assert(ms >= 0, 'date must be in the past')

  var dur = moment.duration(ms, 'milliseconds')
  switch (true) {
  case dur.lt(1, 'minute'):
    return Math.max(Math.floor(dur.as('seconds')), 1) + 's'
  case dur.lt(1, 'hour'):
    return Math.floor(dur.as('minutes')) + 'm'
  case dur.lt(1, 'day'):
    return Math.floor(dur.as('hours')) + 'h'
  case dur.lt(1, 'year'):
    return this.format('D MMM')
  default:
    return this.format('D MMM YYYY')
  }
}

_.extend(moment.fn, { fromNowTwitter: fromNowTwitter })