use Helia to test if certain peers are listening on webtransport

find-webtransport-peers.js

import { multiaddr } from '@multiformats/multiaddr'
import { WebTransport } from '@multiformats/multiaddr-matcher'
import { createHelia } from 'helia'

const helia = await createHelia()

const multiaddrs = [
  // fill out multiaddrs for peers you want to check here:
  '/ip4/123.45.67.89/tcp/4001/ipfs/Qmabcdefg...',
  '/ip4/98.76.54.32/tcp/4004/ipfs/bafyka...',
].map(multiaddr)

// group all listed multiaddrs by peerId
const groupedMultiaddrs = multiaddrs.reduce((acc, ma) => {
  const peerId = ma.getPeerId()
  if (!acc[peerId]) {
    acc[peerId] = []
  }
  acc[peerId].push(ma)
  return acc
}, {})
// console.log('groupedMultiaddrs: ', groupedMultiaddrs)

function confirmMultiaddrsSupportWebTransport (multiaddrs) {
  return multiaddrs.some((ma) => WebTransport.matches(ma))
}

// loop through each peerId and try to connect to all of it's multiaddrs
for (const [peerId, multiaddrs] of Object.entries(groupedMultiaddrs)) {
  // console.log('multiaddrs: ', multiaddrs)
  console.log('trying to connect to peerId: ', peerId)
  try {
    const connection = await helia.libp2p.dial(multiaddrs)

    // console.log('Connected, running identify')
    const ctlr = new AbortController()
    const { signal } = ctlr
    setTimeout(() => ctlr.abort(), 60000)

    const response = await helia.libp2p.services.identify.identify(connection, {
      signal
    })

    const { listenAddrs } = response
    if (confirmMultiaddrsSupportWebTransport(listenAddrs)) {
      console.log('confirmed webtransport listen on peerId: ', peerId)
      console.log('listenAddrs: ', listenAddrs)
    }
  } catch (e) {
    console.error(e)
  }
}