union$

Obtain entries present in any object.

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

function union$(x, y, fc)
// x:  an object (updated)
// y:  another object
// fc: combine function (a, b)

const object = require('extra-object');

var x = {a: 1, b: 2, c: 3};
var y = {b: 20, c: 30, d: 40};
object.union$(x, y);
// → { a: 1, b: 2, c: 3, d: 40 }

x;
// → { a: 1, b: 2, c: 3, d: 40 }

var x = {a: 1, b: 2, c: 3};
object.union$(x, y, (a, b) => b);
// → { a: 1, b: 20, c: 30, d: 40 }

References

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