Try it
const map = new Map();
map.set("0", "foo");
map.set(1, "bar");
const iterator = map.keys();
console.log(iterator.next().value);
// Expected output: "0"
console.log(iterator.next().value);
// Expected output: 1
Syntax
js
keys()
Parameters
None.
Return value
A new iterable iterator object.
Examples
Using keys()
js
const myMap = new Map();
myMap.set("0", "foo");
myMap.set(1, "bar");
myMap.set({}, "baz");
const mapIter = myMap.keys();
console.log(mapIter.next().value); // "0"
console.log(mapIter.next().value); // 1
console.log(mapIter.next().value); // {}
Specifications
| Specification |
|---|
| ECMAScript® 2027 Language Specification # sec-map.prototype.keys |