Set Algebra

Perform Set Algebra with JavaScript Sets.

Install

npm install @dnvr/set-algebra

How it works

Set Algebra provides methods to perform Set operations to JavaScript sets.

This includes union, intersection and difference functions and U, I, D which are shorthand aliases for the same functions respectively.

The difference operation is binary while union and intersection allow any number of arguments.

All methods take Iterables as parameters, including Sets and Arrays, and they all return Sets.

Usage

import {

  union, intersection, difference,

  U, I, D

} from '@dnvr/set-algebra'

const firstFive = [ 1, 2, 3, 4, 5 ]
const evenFive = [ 2, 4, 6, 8, 10 ]
const oddFive = [ 1, 3, 5, 7, 9 ]

const firstFiveSet = new Set( firstFive )
const evenFiveSet = new Set( evenFive )
const oddFiveSet = new Set( oddFive )

// All function allow any iterables as parameters

// The following are equivalent and all return Set { 1, 2, 3, 4, 5, 6, 8, 10 }
union( firstFive, evenFive )
union( firstFiveSet, evenFive )
union( firstFive, evenFiveSet )
union( firstFiveSet, evenFiveSet )

// The following will return Set { 2, 4 }
intersection( firstFive, evenFive )

// The functions union and intersection can take any number of parameters in any order
union() // returns Set {}
union( firstFive ) // returns Set { 1, 2, 3, 4, 5 }
union( firstFive, evenFive, oddFive ) // returns Set { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }

intersection() // returns Set {}
intersection( firstFive ) // returns Set { 1, 2, 3, 4, 5 }
intersection( firstFive, evenFive, oddFive ) // returns Set {}

// The difference function takes 2 parameters and the order matters
// The following will return Set { 1, 3, 5 }
difference( firstFive, evenFive )

// The following will return Set { 6, 8, 10 }
difference( evenFive, firstFive )

// The difference function acts similarly to union and intersection without both parameters present
difference() // returns Set {}
difference( firstFive ) // returns Set { 1, 2, 3, 4, 5 }

// U, I and D are equivalent to union, intersection and difference and can be used instead
U( evenFive, oddFive ) // returns Set { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
I( evenFive, oddFive ) // returns Set {}
D( evenFive, oddFive ) // returns Set { 2, 4, 6, 8, 10 }
D( oddFive, evenFive ) // returns Set { 1, 3, 5, 7, 9 }