JavaScript Set() as it should be.

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. The API is similar to how sets work in Python.

Additions to the default ECMAScript 6 set

• ∪ union
• ∩ intersection
• - difference/subtract
• ⊖ symmetric difference
• ⊆ subset
• ⊇ superset
• map
• filter
• reduce

Install

$ npm install --save zet

Usage

const Zet = require('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 funciont 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