example.js

var multifeed = require('.')
var ram = require('random-access-memory')

var multi = multifeed('./db', { valueEncoding: 'json' })

// a multifeed starts off empty
console.log(multi.feeds().length)             // => 0

// create as many writeable feeds as you want; returns hypercores
multi.writer('local', function (err, w) {
  console.log(w.key, w.writable, w.readable)   // => Buffer <0x..> true true
  console.log(multi.feeds().length)             // => 1

  // write data to any writeable feed, just like with hypercore
  w.append('foo', function () {
    var m2 = multifeed(ram, { valueEncoding: 'json' })
    m2.writer('local', function (err, w2) {
      w2.append('bar', function () {
        replicate(multi, m2, function () {
          console.log(m2.feeds().length)        // => 2
          m2.feeds()[1].get(0, function (_, data) {
            console.log(data)                   // => foo
          })
          multi.feeds()[1].get(0, function (_, data) {
            console.log(data)                   // => bar
          })
        })
      })
    })
  })
})

function replicate (a, b, cb) {
  var r = a.replicate(true)
  r.pipe(b.replicate(false)).pipe(r)
    .once('end', cb)
    .once('error', cb)
}