samle.js

class Connection extends DuplexStream {
  static isConnection (conn) {
    return conn && conn._stream && conn.getPeerInfo
  }

  constructor (stream) {
    this._stream = stream
  }

  get stream () {
    return this._stream
  }

  set peerInfo (info) {
    this._peerInfo = info
  }

  getPeerInfo (cb) {
    cb(null, this._peerInfo)
  }

  // Implement stream methods to pass through to this._stream
}

class WrappedConnection extends Connection {
  static isWrappedConnection (conn) {
    return conn._connection && Connection.isConnection(conn._connection)
  }

  constructor (conn) {
    assert(Connection.isConnection(conn))
    this._connection = conn
  }

  get stream () {
    return this._connection.stream
  }

  set peerInfo (info) {
    this._connection.peerInfo = info
  }

  getPeerInfo (cb) {
    this._connection.getPeerInfo(cb)
  }
}

class IdentifyConnection extends WrappedConnection {
  static isIdentifyConnection (conn) {
    return Connection.isConnection(conn) && conn._identify
  }

  constructor (conn) {
    assert(Connection.isConnection(conn))
    super(conn)
  }

  _identify (cb) {
  }

  getPeerInfo (cb) {
    this._identify((err, info) => {
      this.peerInfo = info
      super.getPeerInfo(cb)
    })
  }
}


class SecioConn extends WrappedConnection {
  constructor (conn) {
    assert(IdentifyConnection.isIdentifyConnection(conn))
    super(conn)
  }
}

const listener = transport.createListener((conn) => {
  const identifiedConn = new IdentifyConnection(conn)

  conn.getPeerInfo(cb) // nothing as no peerInfo is set
  identifiedConn.getPeerInfo(cb) // will do identify and call back with the info

  const secureConn = new SecioConn(identifiedConn)
})