set-extended

This module's aim is to expand the already available functionalities of the Set Class in JS to cover most of the usual operators when using applied Set Theory, such as: Union, Intersection or Symetric Difference of sets, Power Set, Cartesian Product, and so on.

Installation

set-extended is available on npm package manager.

npm install set-extended

Usage

First, import the module. I like to call it SuperSet, as it gives super powers to the Set class.

const SuperSet = require('set-extended');

Evaluate if a set is a subset of a set:

MySet.subsetOf(A)

const A = SuperSet.of([1,2]);
const B = SuperSet.of([1,2,3,4,5]);

console.log(A.subsetOf(B))
console.log(B.subsetOf(A))
---
true
false

Union of sets:

SuperSet.union(...args)

const A = SuperSet.of([1,2,3]);
const B = SuperSet.of([3,4,5]);
const C = SuperSet.union(A,B);

console.log(C)
---
SuperSet [Set] {1, 2, 3, 4, 5}

Intersection of sets

SuperSet.intersection(...args)

const A = SuperSet.of([1,2,3]);
const B = SuperSet.of([3,4,5]);
const C = SuperSet.intersection(A,B);

console.log(C)
---
SuperSet [Set] {3}

Cartesian product of 2 sets

SuperSet.cartesianProduct(A,B)

const A = SuperSet.of([1,2]);
const B = SuperSet.of([1,2,3]);
const C = SuperSet.cartesianProduct(A,B);

console.log(C)
---
SuperSet [Set] { [ 1, 1 ], [ 1, 2 ], [ 1, 3 ], [ 2, 1 ], [ 2, 2 ], [ 2, 3 ] }

Difference of 2 sets

MySet.difference(A)

const A = SuperSet.of([1,2]);
const B = SuperSet.of([1,2,3,4]);
const C = B.difference(A);

console.log(C)
---
SuperSet [Set] { 3, 4 }

Symmetric Difference of 2 sets

MySet.symmetricDifference(A)

Remember: The Symmetric Difference of two sets is the set of elements which are in either of the sets and not in their intersection.

const A = SuperSet.of([1,2]);
const B = SuperSet.of([1,2,3,4]);
const C = A.symmetricDifference(B);

console.log(C)
---
SuperSet [Set] { 1, 2, 5, 6 }

Cardinal of a Set

MySet.cardinal

Remember: We name cardinal of a Set to it's size. Similar to .length on an array

const A = SuperSet.of([1,2,3,4,5]);

console.log(A.cardinal)
---
5

Power Set of a Set

MySet.powerSet

Remember: The definition of the power set is the set of all the possibles subsets of a certain set: Power Set

const A = SuperSet.of([1,2]);

console.log(A.powerSet)
---
SuperSet [Set] {
  SuperSet [Set] {},
  SuperSet [Set] { 2 },
  SuperSet [Set] { 1 },
  SuperSet [Set] { 1, 2 } 
}

Contributing

Pull requests are welcome.

License

MIT