set-manipulator

ES6 set manipulation operations based on https://gist.github.com/jabney/d9d5c13ad7f871ddf03f

Set operations take two arrays and return the result of the operation as an array. Supported operations are union, intersection, difference, complement, and equals. difference is the symmetric difference and complement is the relative complement. The set operations are fast, even for large arrays.

Installation

npm install set-manipulator

Usage

import {
  union,
  intersection,
  difference,
  complement,
  equals,
} from 'set-manipulator';
const a = [1, 1, 2, 3, 3]; // [1, 2, 3]
const b = [3, 4, 4, 5, 5]; // [3, 4, 5]

// Join two sets together. A ∪ B
union(a, b); // => [1, 2, 3, 4, 5]

// The intersection of two sets. A ∩ B
intersection(a, b); // => [3]

// The symmetric difference of two sets. A Δ B
difference(a, b); // => [1, 2, 4, 5]

// The relative complement, or a minus b. A\B
complement(a, b); // => [1, 2]

// Set equality. A = B
equals(a, b); // => false
equals(a, [1, 2, 3]); // => true

Using Objects

Arrays of objects can be used in set operations as long as they have some type of unique identifier. A custom identity extractor method can be specified as a third argument to any of the set manipulation functions.

import { union } from 'set-manipulator';
const a = [{ id: a, number: 1 }, { id: b, number: 2 }];
const b = [{ id: c, number: 5}];

// Join two sets together. A ∪ B
union(a, b, (object) => object.id); // => [{ id: a, number: 1 }, { id: b, number: 2 }, { id: c, number: 5 }];