Generalized set operations and comparisons in the style of Haskell
npm install subsetSubset provides basic and generalized set operations for JavaScript.
They are inspired by a subset of the interface to Haskell's Data.List, but optimized for JavaScript semantics.
The new ES6 Set class is not particularly helpful for doing set operations on general objects (as their only version of equality is ===), and this module provides a general alternative for people who want to do the same-ish things on arrays.
import syntax or attach it to the short variable of choice. For selling points, here's how it will look with ES7 modules.``js
import { equality, union, unionBy, intersect, unique, uniqueBy, insert, delete, group } from 'autonomy'
intersect([1,2,3,4], [2,4,6,8]); // [ 2, 4 ]
union([1,3,5], [4,5,6]); // [ 1, 3, 5, 4, 6 ]
unionBy(equality('a'), [{ a: 1 }, { a: 3 }], [{ a: 2 }, { a: 3 }]);
// [ { a: 1 }, { a: 3 }, { a: 2 } ]
unique([1,3,2,4,1,2]); // [ 1, 3, 2, 4 ]
var notCoprime = (x, y) => gcd(x, y) > 1;
var primes = uniqueBy(notCoprime, [2,3,4,5,6,7,8,9,10,11,12]); // [ 2, 3, 5, 7, 11 ]
group([1,2,2,3,5,5,2]); // [ [1], [2,2], [3], [5,5], [2] ]
insert([1,2,3,4], 3); // [ 1, 2, 3, 3, 4 ]
delete([1,2,3,2,3], 2); // [ 1, 3, 2, 3 ]
``
Read the full API.
Note that it is often useful to get it with the larger utility library interlude for which it was made.