ECMAScript 6 sets have no methods for computing the union (∪), intersection (∩) or difference (⊖). Zet is an extension of ES6 Set and comes with all its functionality included with extra set logic. The API is similar to how sets work in Python.

Features

Additions to the default ECMAScript 6 set

• Union (∪)
• Intersection (∩)
• Difference/subtract (-)
• Symmetric difference (⊖)
• Subset (⊆)
• Superset (⊇)
• Map
• Filter
• Reduce

Additionally, this module is delivered as:

• ES Module: dist/zet.mjs
• CommonJS: dist/zet.js
• UMD: dist/zet.umd.js

Install

$ npm install --save zet

Usage

import Zet from 'zet';

let a = new Zet([1, 2, 3]);
let b = new Zet([3, 4, 5]);
let c = new Zet([2, 3, 4]);

Zet.union(a, b);
//=> [Zet] {1, 2, 3, 4, 5}

a.union(b, c);
//=> [Zet] {1, 2, 3, 4, 5}

a.intersection(b);
//=> [Zet] {3}

a.symmetricDifference(c);
//=> [Zet] {1, 4}

a.subset(b);
//=> false

a.filter(i => i % 2);
//=> [Zet] {1, 3}

API

Zet([iterable])

Returns:Zet

Returns the Zet instance.

Zet extends Set() and inherit all its functionality, like has(), size() etc.

Zet.union(...sets) ∪

Returns:zet

Static variadic function that return a new set with elements from all other sets.

sets

Type: Zet|Set

Two or more sets of type Zet or Set.

Zet.intersection(...sets) ∩

Returns:zet

Static variadic function that return a new set with elements common to this and all other sets.

sets

Type: Zet|Set

Two or more sets of type Zet or Set.

Zet.difference(...sets) - or \

Returns:zet

Returns the difference between two or more sets. The order of the sets matters. Sets are differentiated against the first argument/set.

sets

Type: Zet|Set

Two or more sets of type Zet or Set.

Zet.symmetricDifference(setA, setB) ⊖ or ∆

Returns:zet

Static function that return a new set with elements in either setA or setB but not both.

setA

Type: Zet|Set

Set A of type Zet or Set.

setB

Type: Zet|Set

Set B of type Zet or Set.

Zet.subset(setA, setB)

Returns: Boolean

Test whether every element in setB is in setA.

setA

Type: Zet|Set

Set of type Zet or Set.

setB

Type: Zet|Set

Set of type Zet or Set.

Zet.superset(setA, setB)

Returns: Boolean

Test whether every element in setA is in setB.

setA

Type: Zet|Set

Set of type Zet or Set.

setB

Type: Zet|Set

Set of type Zet or Set.

map(set, func)

Returns: Zet|Set

Creates a set with the results of calling the provided function on every element.

set

Type: Zet|Set

Set of type Zet or Set.

func

Type: Function

Function that produces an element of the new set.

filter(set, func)

Returns: Zet|Set

Creates a set with all elements that pass the test implemented by the provided function.

set

Type: Zet|Set It is the set going to be examined.

func

Type: Function

It is a predicate, to test each element of the set.

reduce(set, func, initializer)

Returns: Number

Reduces the set to a single value, by executing the provided function for each element in the set (from left-to-right).

set

Type: Zet|Set

Set of type Zet or Set.

func

Type: Function

Function to be executed for each element in the set.

initializer

Type: Number

Optional. A value to be passed to the function as the initial value.

Instance Methods

union(...sets) ∪

Returns:zet

Variadic method that return a new set with elements from this and all other sets.

sets

Type: Zet|Set

One or more sets of type Zet or Set.

intersection(...sets) ∩

Returns:zet

Variadic method that return a new set with elements common to this and all other sets.

sets

Type: Zet|Set

One or more sets of type Zet or Set.

difference(...sets) - or \

Returns:zet

Variadic method tht return a new set with elements in this that are not in the other sets.

sets

Type: Zet|Set

One or more sets of type Zet or Set.

symmetricDifference(other) ⊖ or ∆

Returns:zet

Method that return a new set with elements in either this or other but not both. This is also known as xor.

other

Type: Zet|Set

Set of type Zet or Set.

subset(other)

Returns: Boolean

Test whether every element in the set is in other.

other

Type: Zet|Set

Set of type Zet or Set.

superset(other)

Returns: Boolean

Test whether every element in other is in the set.

other

Type: Zet|Set

Set of type Zet or Set.

map(func)

Returns: Zet|Set

Creates a set with the results of calling the provided function on every element.

func

Type: Function

Function that produces an element of the new set.

filter(func)

Returns: Zet|Set

Creates a set with all elements that pass the test implemented by the provided function.

func

Type: Function

It is a predicate, to test each element of the set.

reduce(func, initializer)

Returns: Number

Reduces the set to a single value, by executing the provided function for each element in the set (from left-to-right).

func

Type: Function

Function to be executed for each element in the set.

initializer

Type: Number

Optional. A value to be passed to the function as the initial value.

License

MIT © Terkel Gjervig