bloom

A little Node app that demonstrates how a bloom filter works by adding words to a customizable
filter and checking if a word has already been added. A second feature is a 225k+ dictionary that can be loaded and used to check for false positives by matching random strings.

Install

You'll need Node.js installed on your computer in order to install and run this app.

git clone https://github.com/cobergmd/bloom
cd bloom
npm install
npm start 

You can run the tests with:

npm test

Usage

After you have started the Node app, open a browser and navigate to http://localhost:9292

There are two features on the web page, the first allows you to test a configurable bloom filter by adding words and checking for others. The second feature allows you to load a large word file and then check for false positive searches by generating gibberish words and seeing if they get positive hits on the filter.

Modules

bloom

const bloom = require('./bloom');

let filter = new bloom();

filter.add('apple'); // add a word to the filter
var result = filter.exists('xykadjsoinv'); // returns true or false

bloom.add(word)

Add a new word to the filter

bloom.exists(word)

Returns true if the word hash is found in the filter

wordlist

const WordList = require('wordlist')

var opts ={
    wordFile: "path/wordfile.txt",
    filterSize: 4096,
    hashCount: 5
}

let wordList = new WordList(opts);

wordlist.getWord(word)

Returns an object containing the word value and properties that specify if the word was a match and if it was a false positive match.

wordlist.wordCount()

Returns the number of words in the list cache.