union$

Gives values present in any array. 📦 😺 🏃 📼 🌔 📜 📰 📘

Alternatives: union, union$.
Similar: union, intersection, difference, symmetricDifference.

array.union$(x, y, [fc], [fm]);
// x:  an array (updated)
// y:  another array
// fc: compare function (a, b)
// fm: map function (v, i, x)
// → x

⏱️ Compare function => O(n²).

const array = require("extra-array");

var x = [1, 2, 3, 4];
var y = [2, 3, 5];
array.union$(x, y);
// [ 1, 2, 3, 4, 5 ]

x;
// [ 1, 2, 3, 4, 5 ]

var x = [1, 2, 3, 4];
var y = [-2, -3, -5];
array.union$(x, y, (a, b) => Math.abs(a) - Math.abs(b));
// [ 1, 2, 3, 4, -5 ]

var x = [1, 2, 3, 4];
array.union$(x, y, null, v => Math.abs(v));
// [ 1, 2, 3, 4, -5 ]

References

• Data.Set.union: Haskell
• Set.union: Python
• _.union: lodash
• _.unionBy: lodash
• _.unionWith: lodash
• Array.union: sugarjs