JavaScript: Map.prototype.keys

By Xah Lee. Date: . Last updated: .

New in ES2015.

Map.prototype.keys()

Returns a iterator for the keys in the map.

〔►see JavaScript: Iterator

var 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. JavaScript: the Map Object Tutorial
  2. JavaScript: Map Object
  3. JavaScript: Map.prototype
  4. JavaScript: Iterate Over Map Object
  5. JavaScript: Convert Object to Map Data Type
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