Judy Arrays for Node.js

Judy Arrays are fast, memory efficient, ordered associative arrays.

Example

var Judy = require('judy-ffi');

var j = new Judy();

j.put('cow', 'moo');

console.log('A cow goes', j.get('cow')); // A cow goes moo

j.put('bird', 'coo');

j.size();			// 2

j.find();			// [ {'bird': 'coo'}, {'cow': 'moo'} ]
j.find('b');		// [ {'bird': 'coo'} ]
j.find('c');		// [ {'cow': 'moo'} ]
j.find('b', 'c');	// [ {'bird': 'coo'} ]

j.forEach(function(k,v) {
	console.log('A %s goes %s', k, v);
});
// A bird goes coo
// A cow goes moo

j.delete_all('c');	// [ 'cow' ]
j.find();			// [ {'bird': 'coo'} ]

j.delete_all();		// [ 'bird' ]
j.find();			// []

Requirements

• libjudy
  • Debian-based: apt-get install libjudy
  • OSX: brew install judy

API

• Judy()
• Judy#size()
• Judy#put()
• Judy#get()
• Judy#delete()
• Judy#delete_all()
• Judy#find()
• Judy#forEach()

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Judy()

new Judy() returns a new Judy Array instance.

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Judy#size()

size() to get number of entries.

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Judy#put(key, value)

put() to store new entries or overwrite existing entries in Judy array.

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Judy#get(key)

get() to retrieve entries from Judy array.

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Judy#delete(key)

delete() to delete an entry from Judy array.

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Judy#delete_all(prefix, maxKey)

delete_all() to delete all keys starting with prefix and less than maxKey

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Judy#find(prefix, maxKey)

find() to search for all entries with keys starting with prefix and less than maxKey

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Judy#forEach(prefix, maxKey, cb)

forEach() to iterate through entries with keys starting with prefix and less than maxKey. The callback is invoked with the key and value of each matched entry.