sorted-set

A sorted set based heavily upon redis' skip list implementation. The module named sorted-map separates keys and values similar to redis' implementation.

Test

Run any of the following:

$ mocha
$ npm test
$ make test

Note: remember to npm install!

Install

$ npm install sorted-set

API

var Set = require('sorted-set');

var set = new Set();

// average O(log(N))
set.add('5a600e16');
set.add('5a600e17');
set.add('5a600e18'); // => null
set.add('5a600e17'); // => '5a600e17'

// average O(1)
set.has('5a600e17'); // => true

// average O(1)
set.get('5a600e17'); // => '5a600e17'

// average O(log(N))
set.del('5a600e16'); // => '5a600e16'

// average O(1)
set.del('5a600e16'); // => null

set.add('5a600e10');
set.add('5a600e11');
set.add('5a600e12');
set.add('5a600e13');
set.add('5a600e14');
set.add('5a600e15');
set.add('5a600e16');

// average O(log(N)+M) where M is the number of elements between min and max
set.range('5a600e13', '5a600e14'); // inclusive
// => ['5a600e13', '5a600e14']

set.range('5a600e15');
// => ['5a600e15', '5a600e16', '5a600e17', '5a600e18']

// average O(log(N)+log(M)) where M as in range
set.count('5a600e13', '5a600e14'); // => 2

// more or less indexOf for the sorted values
// average O(log(N))
set.rank('5a600e16'); // => 6
set.rank('5a600e13'); // => 3
set.rank('5a600e14'); // => 4
set.rank('5a600e15'); // => 5
set.rank('5a600e19'); // => -1

// average O(log(N)+M) where M as in range
set.slice(0, 3);
// => ['5a600e10', '5a600e11', '5a600e12']

set.slice(-1); // => ['5a600e18']

set.length; // => 9

set.shift(); // => '5a600e10'

set.pop(); // => '5a600e18'

set.head(); // => '5a600e11'

set.tail(); // => '5a600e17'

Intersection

This form of intersection intersects based on the comparison of values.

var a = new Set(), b = new Set();

a.add('5a600e10');
a.add('5a600e12');
a.add('5a600e14');
a.add('5a600e15');
a.add('5a600e17');
a.add('5a600e18');
a.add('5a600e19');
a.add('5a600e1a');
a.add('5a600e1b');
a.add('5a600e1c');
a.add('5a600e1e');

b.add('5a600e10');
b.add('5a600e11');
b.add('5a600e13');
b.add('5a600e14');
b.add('5a600e15');
b.add('5a600e17');
b.add('5a600e19');
b.add('5a600e1b');
b.add('5a600e1c');
b.add('5a600e1d');
b.add('5a600e1f');

Set.intersect(a, b);
// => ['5a600e10', '5a600e14', '5a600e15', '5a600e17', '5a600e19', '5a600e1b', '5a600e1c']

Set.intersect(b, a);
// => ['5a600e10', '5a600e14', '5a600e15', '5a600e17', '5a600e19', '5a600e1b', '5a600e1c']

// works, but not preferred
a.intersect(b);
// => ['5a600e10', '5a600e14', '5a600e15', '5a600e17', '5a600e19', '5a600e1b', '5a600e1c']

var c = new Set();

c.add('5a600e10');
c.add('5a600e12');
c.add('5a600e13');
c.add('5a600e14');
c.add('5a600e16');
c.add('5a600e17');
c.add('5a600e18');
c.add('5a600e1a');
c.add('5a600e1c');
c.add('5a600e1f');

// for best performance, the smallest set should be first
Set.intersect(c, a, b);
// => ['5a600e10', '5a600e14', '5a600e17', '5a600e1c']

This form of intersect intersects based on the hash of the value. This version is also slower, because the set is not necessarily ordered by the hash of its values.

var a = new Set(), b = new Set();

a.add('5a600e10');
a.add('5a600e12');
a.add('5a600e13');
a.add('5a600e14');
a.add('5a600e16');
a.add('5a600e17');
a.add('5a600e18');
a.add('5a600e1a');
a.add('5a600e1c');
a.add('5a600e1f');

b.add('5a600e10');
b.add('5a600e11');
b.add('5a600e13');
b.add('5a600e14');
b.add('5a600e15');
b.add('5a600e17');
b.add('5a600e19');
b.add('5a600e1b');
b.add('5a600e1c');
b.add('5a600e1d');
b.add('5a600e1f');

Set.intersectKeys(a, b);

Custom Hashing and Comparison

Caution: this often involves adding objects to the set. When you add an object to the set, make sure to not change the data in the object by reference without updating the set, unless the update doesn't alter the result of hashing or comparison.

var set = new Set({
  // what the primary index should be (defaults to identity function)
  hash: function(entry) {
    return entry % 50;
  },
  // how to order the set (defaults to string-friendly comparator)
  compare: function(a, b) {
    // descending numeric sort
    return b - a;
  }
});

set.add(22);
set.add(72); // replaces 22 because it hashes to the same value
set.add(40);

// descending order
set.values(); // [72, 40]

Unique

You can enable unique values with the unique option, which causes set to throw an error if the value provided already belongs to a different key.

var set = new Set({
  unique: true,
  hash: function(item) {
    return item.key;
  },
  compare: function(a, b) {
    return a.value - b.value;
  }
});

set.add({key: '5a600e10', value: 16});
set.add({key: '5a600e11', value: 6});
set.add({key: '5a600e12', value: 17});
set.add({key: '5a600e13', value: 11});
set.add({key: '5a600e14', value: 14});
set.add({key: '5a600e15', value: 19});
set.add({key: '5a600e16', value: 3});
set.add({key: '5a600e17', value: 12});
set.add({key: '5a600e18', value: 10});

// currently O(log(N)) because it needs to attempt to insert the value
set.add({key: '5a600e19', value: 11}); // throws
set.add({key: '5a600e14', value: 14}); // => {key: '5a600e14', value: 14}

TODO: all tests need to check compare and hash support.

License

The MIT License (MIT)

Copyright © 2014 GlobeSherpa

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.