sequential-hash

A lexicographical ordered rolling hash

npm install sequential-hash

Usage

var seqhash = require('sequential-hash')
var hash = seqhash('sha256') // sha256 is the hash algorithm

var prev = null
var words = ['mathias', 'wrote', 'this']

words.forEach(function (word) {
  prev = hash(word, prev)
  console.log(prev + ' -> ' + word)
})

Running the above produces

00!c1768bf97517f3da6948ee49b4d7078890c910a9fc07065a382184a4a3d9457a -> mathias
01!f16200e82c592e37e0f938c12ba4b3d88aa61b1df873ab03b60932956211ec03 -> wrote
02!34efbd1375266a04c302de321196d0a029bee922ca8044fe2cf8ca38289e3333 -> this

API

hash = seqhash(algo)

Create a rolling hash function based on a hash algorithm (sha1, sha256, etc)

hashString = hash(value, [previousHash])

Hash a value based on a previous hash. The returned hashString is guaranteed to sort lexicographically higher than previousHash.

License

MIT