turbo-hash-map

Fast Map built for keys that are always fixed size uniformly distributed buffers.

npm install turbo-hash-map

Uses a prefix trie to map hashes to values in an effectice manner.

Usage

const HashMap = require('turbo-hash-map')

const map = new HashMap()

map.set(hash('hello world'), 'a value')

function hash (val) { // any hash algo without practical collisions will work
  return crypto.createHash('sha256').update(val).digest()
}

API

const m = new HashMap()

Create a new HashMap. The HashMap follows the api of a JS map, except keys are buffers containing hashes.

m.set(hash, value)

Insert a value with a hash as the key. Hash should be a fixed size buffer.

const value = m.get(hash)

Get the value out. Returns undefined if the value cannot be found.

const bool = m.has(hash)

Does the map have it?

const deleted = m.delete(hash)

Delete an entry.

m.size

How many entries?

m.clear()

Delete all entries.

...m

Iterate the map. Yields arrays of [hash, value].

...m.keys()

Key (hash) iterator.

...m.values()

Value iterator.

Performance

There is a bench included. On my macbook this yields

turbo-hash-map-set: 2.068s
turbo-hash-map-get: 1.931s
js-map-set: 16.078s
js-map-get: 6.626s

License

MIT