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async function* expression

The async function* keywords can be used to define an asynchronous generator function inside an expression.

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Syntax

async function* (param0) {
  statements
}
async function* (param0, param1) {
  statements
}
async function* (param0, param1, /* … ,*/ paramN) {
  statements
}

async function* name(param0) {
  statements
}
async function* name(param0, param1) {
  statements
}
async function* name(param0, param1, /* … ,*/ paramN) {
  statements
}

Parameters

name Optional: The function name. Can be omitted, in which case the function is anonymous. The name is only local to the function body.
paramN Optional: The name of an argument to be passed to the function. A function can have up to 255 arguments.
statements Optional: The statements which comprise the body of the function.

Description

An async function* expression is very similar to and has almost the same syntax as a async function* statement. The main difference between an async function* expression and an async function* statement is the function name, which can be omitted in async function* expressions to create anonymous asynchronous generator functions. See also the chapter about functions for more information.

Examples

Using async function*

The following example defines an unnamed asynchronous generator function and assigns it to x. The function yields the square of its argument:

const x = async function* (y) {
  yield Promise.resolve(y * y);
};
x(6).next().then((res) => console.log(res.value)); // logs 36

Specifications

Specification
ECMAScript Language Specification # sec-async-generator-function-definitions

Browser compatibility

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	Deno	Node.js
`async_function*`	63	79	55	No	50	12	63	63	55	46	12	8.0	1.0	10.0.0 8.10.0