Async generatorsBaseline · Widely available

Async generator functions (async function*) create iterators that return multiple promises, one after another, on-demand.

Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Jan 15, 2020. Widely available since Jul 15, 2022.

How to use ↓Compare browsers

Browser support

DesktopChrome

1–62Not supported

63+Supportedsince Dec 6, 2017

Current: 155

Edge

12–18Not supported

79+Supportedsince Jan 15, 2020

Current: 154

Firefox

1–56Not supported

57+Supportedsince Nov 14, 2017

Current: 157

Safari

1–11.1Not supported

12+Supportedsince Sep 17, 2018

Current: 27

MobileChrome Android

18–62Not supported

63+Supportedsince Dec 5, 2017

Current: 155

Firefox Android

4–56Not supported

57+Supportedsince Nov 28, 2017

Current: 157

Safari iOS

1–11.3Not supported

12+Supportedsince Sep 17, 2018

Current: 27

How to use

This feature is Baseline widely available — use it freely, no fallback needed.

Example

Full syntax and examples are on MDN: AsyncGenerator.

Feature detection

JS · check before using

// Syntax can't be tested with an if-statement — an unsupported
// browser fails to parse the whole script. Either transpile for older
// targets (e.g. Babel/TypeScript/esbuild), or probe in isolation:
let supported = true;
try {
  new Function("/* code that uses the syntax */");
} catch {
  supported = false;
}

This is a language syntax feature.

Documentation (MDN)

Specification

Sub-features

Support for each part of the feature (9). The overall table above shows when the whole feature works.

Sub-feature	Chrome	Edge	Firefox	Safari	Chrome Android	Firefox Android	Safari iOS
AsyncGenerator	63	79	55	12	63	55	12
AsyncGenerator.next	63	79	55	12	63	55	12
AsyncGenerator.return	63	79	55	12	63	55	12
AsyncGenerator.throw	63	79	55	12	63	55	12
AsyncGeneratorFunction	63	79	55	12	63	55	12
AsyncGeneratorFunction.AsyncGeneratorFunction	63	79	55	12	63	55	12
javascript.functions.method_definitions.async_generator_methods	63	79	57	12	63	57	12
async_generator_function	63	79	57	12	63	57	12
async_generator_function	63	79	57	12	63	57	12