icjs-mpt/readStream.js

This is an implementation of the modified merkle patricia tree as speficed in the Ethereum's yellow paper.

const Readable = require('readable-stream').Readable
const TrieNode = require('./trieNode')
const util = require('util')

module.exports = TrieReadStream

function TrieReadStream (trie) {
  this.trie = trie
  this.next = null
  Readable.call(this, {
    objectMode: true
  })
}

util.inherits(TrieReadStream, Readable)

TrieReadStream.prototype._read = function () {
  var self = this
  if (!self._started) {
    self._started = true
    self.trie._findValueNodes(function (nodeRef, node, key, next) {
      self.push({
        key: TrieNode.nibblesToBuffer(key),
        value: node.value
      })
      next()
    }, function () {
      // close stream
      self.push(null)
    })
  }
}