mini-hamt

Minimal, functional HAMT (Hash Array Mapped Trie) implementation for immutable maps. Similar to other libraries like ImmutableJS or hamt, but without all the frills. Doesn't use prototypes or classes, so you don't have to do anything special to serialize it.

Installation

$ npm install mini-hamt

Usage

Use it as an immutable map. You can set, get, and delete keys from it (no iteration for the time being, post an issue if you want it). If you want to create a new map, just modify the provided empty map.

import * as hamt from 'mini-hamt'
 
const map = hamt.set(hamt.empty, 'test', 1)
hamt.get(map, 'test') === 1
 
const map2 = hamt.set(map, 'test2', 2)
hamt.get(map2, 'test2') === 2
hamt.get(map, 'test2') === undefined
 
const map3 = hamt.del(map2, 'test')
hamt.get(map3, 'test') === undefined
hamt.get(map2, 'test') === 1

API

empty

An empty HAMT. Use this to create your maps, by setting a key on it.

get(map, key)

Read a key

• map - An existing map
• key - The key you want to lookup

Returns: The value of key in map

set(map, key, value)

Set a key/value pair

• map - An HAMT map
• key - The key you want to set
• value - The value you want to assign to key

Returns: A new map with an entry for key equal to value.

del(map, key)

Remove a key

• map - An HAMT map
• key - The key you wish to delete

Returns: A new map without key.

Performance

5,000 ops:

insert 5000: 9ms
lookup 5000: 2ms
delete 2500: 2ms
post-delete lookup 2500: 0ms

50,000 ops:

insert 50000: 58ms
lookup 50000: 14ms
delete 25000: 29ms
post-delete lookup 25000: 7ms

You can run them yourself by running babel src --out-dir lib && node bench.js

License

MIT