Iterator methodsBaseline · Newly available

The Iterator object is an abstract base for objects that implement the iterator protocol. It provides methods common to built-in iterators, such as filter(), find(), map(), and reduce(). You can also use the static method Iterator.from() to convert an existing iterable into an Iterator.

Works in the latest version of every major browser, but older devices may not support it yet. Baseline since Mar 31, 2025.

How to use ↓Compare browsers

Browser support

DesktopChrome

1–121Not supported

122+Supportedsince Feb 20, 2024

Current: 155

Edge

12–121Not supported

122+Supportedsince Feb 23, 2024

Current: 154

Firefox

1–130Not supported

131+Supportedsince Oct 1, 2024

Current: 157

Safari

1–18.3Not supported

18.4+Supportedsince Mar 31, 2025

Current: 27

MobileChrome Android

18–121Not supported

122+Supportedsince Feb 20, 2024

Current: 155

Firefox Android

4–130Not supported

131+Supportedsince Oct 1, 2024

Current: 157

Safari iOS

1–18.3Not supported

18.4+Supportedsince Mar 31, 2025

Current: 27

How to use

Every current browser supports this, but it only became Baseline on Mar 31, 2025. Use it as a progressive enhancement, or keep a fallback if you support older devices.

Example

function* naturals() {
  let n = 1;
  while (true) yield n++;
}

const firstEvenSquares = naturals()
  .filter((n) => n % 2 === 0)
  .map((n) => n * n)
  .take(3)
  .toArray(); // [4, 16, 36]

Feature detection

JS · check before using

if ("Iterator" in Iterator || ("prototype" in Iterator && "Iterator" in Iterator.prototype)) {
  // Iterator.Iterator is available
}

Documentation (MDN)

Specification

tc39.es#sec-iterator-helper-objects ↗

Sub-features

Support for each part of the feature (13). The overall table above shows when the whole feature works.

Sub-feature	Chrome	Edge	Firefox	Safari	Chrome Android	Firefox Android	Safari iOS
Iterator.Iterator	122	122	131	18.4	122	131	18.4
Iterator.drop	122	122	131	18.4	122	131	18.4
Iterator.every	122	122	131	18.4	122	131	18.4
Iterator.filter	122	122	131	18.4	122	131	18.4
Iterator.find	122	122	131	18.4	122	131	18.4
Iterator.flatMap	122	122	131	18.4	122	131	18.4
Iterator.forEach	122	122	131	18.4	122	131	18.4
Iterator.from	122	122	131	18.4	122	131	18.4
Iterator.map	122	122	131	18.4	122	131	18.4
Iterator.reduce	122	122	131	18.4	122	131	18.4
Iterator.some	122	122	131	18.4	122	131	18.4
Iterator.take	122	122	131	18.4	122	131	18.4
Iterator.toArray	122	122	131	18.4	122	131	18.4