ts-set-utils

This library provides a small set of utility functions to Typescript's and Javascript's Set class. The ES6 Set has a relatively small api surface and this library fills some common set use cases. Python built-in set class is used as a api template. Find the package here

API

Union

Signature A ∪ B

function union<T> (...sets: Set<T>[]): Set<T>;

Performs a union on all sets provided. A union merge two or more sets together. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([2, 3, 6])

console.log(union(set1, set2));
// Set<number>: Set([1, 2, 3, 6])

Union Pair

Signature A ∪ B

function unionPair<T1, T2> (a: Set<T1>, b: Set<T2>): Set<T1 | T2>;

Performs a union on two sets of different types. This is a utility method of typescript users to mix the set element types

Example

interface Pet {
  pet: string
}
const set1 = new Set([1, 2, 3])
const set2 = new Set([{ pet: 'dog' }, { pet: 'cat' }])

console.log(union(set1, set2));
// Set<number | Pet>: Set([1, 2, 3 { pet: 'dog' }, { pet: 'cat' }])

Intersection

Signature A ∩ B

function intersection<T> (...sets: Set<T>[]): Set<T>;

Performs a intersection on all sets provided. A intersection finds common elements between two or more sets. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([2, 3, 4])

console.log(intersection(set1, set2));
// Set<number>: Set([2, 3])

Disjoint

Signature A ∩ B = ∅

function disjoint<T> (a: Set<T>, b: Set<T>): boolean;

Determine if two sets are disjoint. Two sets are disjoint when they share no elements. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([2, 3, 4])
const set3 = new Set([10])

console.log(disjoint(set1, set2));
// false

console.log(disjoint(set2, set3))
// true

Subset

Signature B ⊆ A

function subset<T> (a: Set<T>, b: Set<T>): boolean;

Determine if set B is a subset of set A. A set B is a subset of A if all elements of B are in set A. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([3, 4, 5])
const set3 = new Set([1, 2])

console.log(subset(set1, set2));
// false

console.log(subset(set1, set3));
// true

console.log(subset(set3, set1));
// false

Set Equal

Signature B = A or B ⊆ A && B ⊇ A

Determine if set B is equal to set A. From the wikipedia definition "Set A and B are equal if and only if they have precisely the same element". Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([3, 4, 5])
const set3 = new Set([1, 2])

console.log(setEqual(set1, set2));
// false

console.log(setEqual(set2, set3));
// false

console.log(setEqual(set1, set1));
// true

Proper Subset

Signature B ⊂ A

function properSubset<T> (a: Set<T>, b: Set<T>): boolean;

Determine if set B is a proper subset of set A. A set B is a proper subset of A if all elements of B are in set A and A is a strictly larger. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([1, 2])

console.log(properSubset(set1, set1));
// false

console.log(subset(set1, set2));
// true

Difference

Signature A \ B

function difference<T> (a: Set<T>, b: Set<T>): Set<T>;

Calculate the set difference between set A and B. A set difference calculates a base set A with a set B removed. More formally this would be called the relative complement. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([3, 4, 5])

console.log(difference(set1, set2));
// Set<number>: Set([1, 2])

Symmetric Difference

Signature A ∆ B

function symmetricDifference<T>(...set<T>[]): Set<T>;

Calculate the symmetric difference between a collection of sets. A symmetric difference of two sets produces a set where elements are members of one set but not the other. The behavior is more complex for more sets. Read more on wikipedia

Example

const set1 = new Set([1, 2, 3])
const set2 = new Set([3, 4, 5])

console.log(symmetricDifference(set1, set2));
// Set<number>: Set([1, 2, 4, 5])