concat$

Append entries from maps, preferring last.

Alternatives: concat, concat$.

function concat$(x, ...ys)
// x:  a map (updated)
// ys: other maps

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

var x = new Map([['a', 1], ['b', 2]]);
var y = new Map([['c', 3], ['d', 4]]);
map.concat$(x, y);
// → Map(4) { 'a' => 1, 'b' => 2, 'c' => 3, 'd' => 4 }

x;
// → Map(4) { 'a' => 1, 'b' => 2, 'c' => 3, 'd' => 4 }

var x = new Map([['a', 1],  ['b', 2]]);
var y = new Map([['c', 3],  ['d', 4]]);
var z = new Map([['d', 40], ['e', 50]]);
map.concat$(x, y, z);
// → Map(5) { 'a' => 1, 'b' => 2, 'c' => 3, 'd' => 40, 'e' => 50 }

References

• Array.prototype.concat: MDN web docs
• Array.add: sugarjs