dumb bloom filter based on a single hash function that adds up the ASCII of a given key string.

dumb_bloom.js

module.exports = {
  bitArray: Array.apply(null, new Array(100)).map(Number.prototype.valueOf, 0),
  hash: function(key) {
    return key.split('')
      .map(function(element) {
        return element.charCodeAt(0);
      })
      .reduce(function(a, b) {
        return a + b;
      });
    },
  insert: function(key) {
    // compute the index of the hash of the key,
    // modulo the size of the array
    this.bitArray[(this.hash(key) % this.bitArray.length) - 1] = 1;
    return true;
  },
  search: function(key) {
    var index = (this.hash(key) % this.bitArray.length) - 1;
    if(this.bitArray[index] === 1) {
      return true;
    } else {
      return false;
    }
  }
};

dumb_bloom_example.js

var bloom = require('./bloom.js');

var corpus = "the quick brown fox jumps over the lazy dog";

corpus.split(' ')
  .map(function(element) {
    bloom.insert(element);
  });

console.log(bloom.bitArray);
console.log(bloom.search('brown'));