unionKeys - nodef/extra-entries GitHub Wiki
Obtain keys present in any entries.
Similar: unionKeys, intersectionKeys.
function unionKeys(...xs)
// xs: all entries
const entries = require('extra-entries');
var x = ["a", 1], ["b", 2], ["c", 3], ["d", 4](/nodef/extra-entries/wiki/"a",-1],-["b",-2],-["c",-3],-["d",-4);
var y = ["b", 20], ["c", 30], ["e", 50](/nodef/extra-entries/wiki/"b",-20],-["c",-30],-["e",-50);
entries.unionKeys(x, y);
// → Set(5) { "a", "b", "c", "d", "e" }