Dream DatArchive API for extensions / peers

DatArchive.dream.js

const archive = await DatArchive.load('someurl', {
  // Gets passed down to hyperdrive constructor
  extensions: ['example', 'foo', 'bar']
})

archive.addEventListener('extension', ({detail}) => {
 const {type, message, peer} = detail
 
 if(type === 'foo') {
   // Similar to the hypercore API: https://github.com/mafintosh/hypercore#feedonextension-name-message-peer
   await peer.extension('bar', 'Hello World')
 }
 
 const decoder = new TextDecoder()
 
 // Message is always an ArrayBuffer
 const decoded = decoder.decode(message)
 
 console.log('got message from peer', type, message, peer.id)
})

// Get currently connected peers
const peers = await archive.peers()

for (let peer of peers) {
  await peer.extension('foo', 'Hey, world?')
}

// Broadcast to all peers, same as hyperdrive
await archive.extension('foo', 'Hey, world?')

// Similar to the hyperdrive API
// https://github.com/mafintosh/hyperdrive#archiveonpeer-add-peer
archive.addEventListener('peer-add', ({detail}) => {
  const { peer } = detail
  
  await peer.extension('example', 'example')
})