hyperlog-concestor

compute the most recent common ancestor among nodes in a hyperlog

example

var concestor = require('hyperlog-concestor')
var hyperlog = require('hyperlog')

var db = require('memdb')()
var log = hyperlog(db, { valueEncoding: 'json' })

var links = {
  A: [],
  B: ['A'],
  C: ['B'],
  D: ['C'],
  E: ['D'],
  F: ['B'],
  G: ['F'],
  H: ['G','E'],
  I: ['H']
}

var keys = Object.keys(links)
var nodes = {}, names = {}, hashes = {}

;(function next () {
  if (keys.length === 0) return ready()
  var key = keys.shift()
  var ln = links[key].map(function (link) { return hashes[link] })
  log.add(ln, key, function (err, node) {
    nodes[key] = node
    hashes[key] = node.key
    names[node.key] = key
    next()
  })
})()

function ready () {
  concestor(log, [ hashes.G, hashes.F, hashes.E ], function (err, cons) {
    var cs = cons.map(function (hash) { return names[hash] })
    console.log('CONCESTORS of G, F, E:', cs)
  })
}

output:

CONCESTORS of G, F, E: [ 'B' ]

api

var concestor = require('hyperlog-concestor')

concestor(log, hashes, cb)

Compute the concestor of an array of hashes present in a hyperlog log. cb(err, cons) fires with the array of concestors (there may be ties).

This module is not very coupled to hyperlog. Any log object with a .get(function (err, node) {}) and a node.links array of hashes will work.

install

npm install hyperlog-concestor

license

BSD