JS: Map.prototype.keys

By Xah Lee. Date: . Last updated: .

New in ES2015.

map_obj.keys()

Returns a iterator for the keys in the map map_obj.

〔►see JS: Iterator

const m = new Map([[3, "n3"], [4, "n4"], [5, "n5"] ]);

console.log( m.keys() ); // MapIterator { 3, 4, 5 }

for (let k of m.keys()) { console.log(k) }

// prints
// 3
// 4
// 5

Reference

ECMAScript 2015 §Keyed Collection#sec-map.prototype.keys

Map Topic

  1. JS: the Map Object Tutorial
  2. JS: Map Object
  3. JS: Map.prototype
  4. JS: Iterate Over Map Object
  5. JS: Convert Object to/from Map
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