const msgpack = {
  append(dest, src) {
    return Buffer.concat([dest, src])
  },

  encode(obj) {
    if (typeof obj === 'number') {
      let buf = Buffer.alloc(9)
      buf.writeUInt8(0xce, 0)
      buf.writeUInt32BE(obj, 1)
      return buf
    } else if (typeof obj === 'string') {
      const str = Buffer.from(obj)
      let buf = Buffer.alloc(5 + obj.length)
      buf.writeUInt8(0xdb, 0)
      buf.writeUInt32BE(obj.length, 1)
      str.copy(buf, 5)
      return buf
    }

    throw new Error(`msgpack: unsupported object: ${obj}`)
  },

  pack(obj) {
    console.log(obj)
    let payload = Buffer.from([0x80 | Object.keys(obj).length])

    // We cannot use Object.keys() because
    // `k' must be a Number.
    for (const k in obj) {
      if (k > 0x7f) {
        throw new Error(`msgpack: too large key`)
      }

      payload = this.append(payload, Buffer.from([k]))
      payload = this.append(payload, this.encode(obj[k]))
      console.log(k)
    }
  },

  unpack(obj) {
    console.log(obj)
  }
}