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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

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

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/async_function*