native-hashset

native-hashset

Provides a native hashset implementation for Node. Based around node-hashset but written using nan to provide better support for multiple Node systems (and the first io.js systems).

Typically when a set is needed in JavaScript, it may be sufficient to simply use a JavaScript object:

var set = {};

// add
set['foobar'] = true;

// contains
if (!set['foobar']) {
    // whatever
}

// iterator
Object.keys(set).forEach(function(k){
    console.log(k);
});

This works well for up to a few million items, but after that it starts to grind v8 down to a halt. It also has the negative of only allowing String types.

native-hashset implements a HashSet using std::unsorted_set to enable working with extremely large sets. Naturally this set is strictly typed due to the nature of C++.

Compatibility

If you're using Node.js > v4, please use version >= 0.2.0 of this module, all lower will fail. If you're using anything before Node.js v4, please use < 0.2.0.

This module is built on each commit with TravisCI on the latest stable version of Node.js. In order to maintain support throughout these versions the nan library is used for compatibility across varying Node versions.

Setup

$ npm install native-hashset

Quick Start

var HashSet = require('native-hashset');
var set = new HashSet.String();
set.add('foobar');

var HashSet = require('native-hashset');
var set = new HashSet.Integer();
set.add(1);

HashSet

There are currently two HashSet constructors, HashSet.Integer and HashSet.String.

add(value)

Adds value to the set. Throws an error if value is not the correct type for the set.

buckets()

Returns the native bucket distribution of the unordered_set used under the hood.

clear()

Removes all values from the set.

contains(value)

Returns a boolean value indicating if the set contains value.

count(value)

Returns an Integer count indicating if the set contains value. 1 if exists, 0 if not.

empty()

Returns a boolean value indicating if the set contains any values.

iterator()

Returns an iterator to iterate over the values in the set.

var it = set.iterator();

while (it.hasNext()) {
  console.log(it.next());
}

keys()

Returns an Array containing all keys in the set. Use with caution and on smaller sets.

remove(value)

Removes value from the set.

size()

Returns the numbers of values in the set.

type()

Returns the type of the current set.

Tests

Basic tests are contained in the test/ directory and are designed to be run using Mocha. They can be run using the Makefile via the commands below:

$ npm install
$ make test

Credits

Thanks to inolen for his original HashSet implementation which inspired and provided the groundwork for this module.