nips/34asc.md

NIP-34asc

Ascending

draft optional author:arthurfranca

Events with older created_at are retrieved first.

Motivation

For thread building it may better showing first comments at top to make it easier to understand the context of newer comments.

Implementation

Relay computes nip34asc field once upon receiving the event.

The lower the created_at, the higher nip34asc will be.

Javascript

// Use this same value even if your programming language allows a higher one
const maxDateNowSeconds = 8640000000000 // 8.64e15 ms / 1000
// Equals 17280000000000. It is ok because it is lower than Number.MAX_SAFE_INTEGER
// We multiply by 2 because of "ts = seconds + maxDateNowSeconds" below
const maxTs = maxDateNowSeconds * 2
const maxSecondsLength = maxTs.toString().length

function getNip34asc (createdAt, id = '') {
  // The id length must always be the same to not affect sorting
  // All relays must use the same length
  if (id.length !== 64) { throw new Error('Wrong id length') }
  let seconds = Math.trunc(createdAt) // Make sure it is int instead of float
  if (Number.isNaN(seconds)) { throw new Error('Wrong createdAt') }
  seconds = Math.max(seconds, -maxDateNowSeconds) // Keep min limit
  seconds = Math.min(seconds, maxDateNowSeconds) // Keep max limit
  // Allow negative createdAt but remove minus sign
  // because '-2' string timestamp is wrongly higher than '-1'
  let ts = seconds + maxDateNowSeconds
  // Make it lower the greater the ts is (the newer the createdAt is)
  ts = maxTs - ts
  // '10' is wrongly lower then '2' while '10' is higher than padded '02'
  const paddedTsSeconds = ts.toString().padStart(maxSecondsLength, '0')

  // Event id is used as a fixed length unique identifier
  return `${paddedTsSeconds}${id}`
}

event.nip34asc = getNip34asc(event.created_at, event.id)