ECMA-6.3

var map = new Map ();
mapa.set ('um', 1);
mapa.set ('two', 2);
mapa.set ('three', 3);
for (var key of mapa.keys ()) {
 console.log (key); // one two Three
}
for (var value of mapa.values ​​()) {
 console.log (value); // 1 2 3
}
for (var entry of mapa.entries ()) {
 console.log (input);
}
// output:
// ['one', 1]
// ['two', 2]
// ['three', 3]