stacker.news/lib/nostr.js

import { bech32 } from 'bech32'

export const NOSTR_PUBKEY_HEX = /^[0-9a-fA-F]{64}$/
export const NOSTR_PUBKEY_BECH32 = /^npub1[02-9ac-hj-np-z]+$/
export const NOSTR_MAX_RELAY_NUM = 20
export const NOSTR_ZAPPLE_PAY_NPUB = 'npub1wxl6njlcgygduct7jkgzrvyvd9fylj4pqvll6p32h59wyetm5fxqjchcan'

export function hexToBech32 (hex, prefix = 'npub') {
  return bech32.encode(prefix, bech32.toWords(Buffer.from(hex, 'hex')))
}

export function nostrZapDetails (zap) {
  let { pubkey, content, tags } = zap
  let npub = hexToBech32(pubkey)
  if (npub === NOSTR_ZAPPLE_PAY_NPUB) {
    const znpub = content.match(/^From: nostr:(npub1[02-9ac-hj-np-z]+)$/)?.[1]
    if (znpub) {
      npub = znpub
      // zapple pay does not support user content
      content = null
    }
  }
  const event = tags.filter(t => t?.length >= 2 && t[0] === 'e')?.[0]?.[1]
  const note = event ? hexToBech32(event, 'note') : null

  return { npub, content, note }
}