unionKeys

Gives keys present in any map. 🏃 [:vhs:] 📦 🌔 📒

Similar: unionKeys, intersectionKeys.

map.unionKeys(...xs);
// xs: maps

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

var x = new Map([['a', 1], ['b', 2], ['c', 3], ['d', 4]]);
var y = new Map([['b', 20], ['c', 30], ['e', 50]]);
map.unionKeys(x, y);
// Set(5) { 'a', 'b', 'c', 'd', 'e' }

references

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