File size: 3,671 Bytes
780c9fe |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 |
---
title: AsyncGeneratorFunction
slug: Web/JavaScript/Reference/Global_Objects/AsyncGeneratorFunction
page-type: javascript-class
browser-compat: javascript.builtins.AsyncGeneratorFunction
sidebar: jsref
---
The **`AsyncGeneratorFunction`** object provides methods for [async generator functions](/en-US/docs/Web/JavaScript/Reference/Statements/async_function*). In JavaScript, every async generator function is actually an `AsyncGeneratorFunction` object.
Note that `AsyncGeneratorFunction` is _not_ a global object. It can be obtained with the following code:
```js
const AsyncGeneratorFunction = async function* () {}.constructor;
```
`AsyncGeneratorFunction` is a subclass of {{jsxref("Function")}}.
{{InteractiveExample("JavaScript Demo: AsyncGeneratorFunction", "taller")}}
```js interactive-example
const AsyncGeneratorFunction = async function* () {}.constructor;
const foo = new AsyncGeneratorFunction(`
yield await Promise.resolve('a');
yield await Promise.resolve('b');
yield await Promise.resolve('c');
`);
let str = "";
async function generate() {
for await (const val of foo()) {
str += val;
}
console.log(str);
}
generate();
// Expected output: "abc"
```
## Constructor
- {{jsxref("AsyncGeneratorFunction/AsyncGeneratorFunction", "AsyncGeneratorFunction()")}}
- : Creates a new `AsyncGeneratorFunction` object.
## Instance properties
_Also inherits instance properties from its parent {{jsxref("Function")}}_.
These properties are defined on `AsyncGeneratorFunction.prototype` and shared by all `AsyncGeneratorFunction` instances.
- {{jsxref("Object/constructor", "AsyncGeneratorFunction.prototype.constructor")}}
- : The constructor function that created the instance object. For `AsyncGeneratorFunction` instances, the initial value is the {{jsxref("AsyncGeneratorFunction/AsyncGeneratorFunction", "AsyncGeneratorFunction")}} constructor.
- `AsyncGeneratorFunction.prototype.prototype`
- : All async generator functions share the same [`prototype`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/prototype) property, which is [`AsyncGenerator.prototype`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/AsyncGenerator). Each async generator function created with the `async function*` syntax or the `AsyncGeneratorFunction()` constructor also has its own `prototype` property, whose prototype is `AsyncGeneratorFunction.prototype.prototype`. When the async generator function is called, its `prototype` property becomes the prototype of the returned async generator object.
- `AsyncGeneratorFunction.prototype[Symbol.toStringTag]`
- : The initial value of the [`[Symbol.toStringTag]`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag) property is the string `"AsyncGeneratorFunction"`. This property is used in {{jsxref("Object.prototype.toString()")}}.
These properties are own properties of each `AsyncGeneratorFunction` instance.
- {{jsxref("AsyncGeneratorFunction/prototype", "prototype")}}
- : Used when the function is used as a constructor with the [`new`](/en-US/docs/Web/JavaScript/Reference/Operators/new) operator. It will become the new object's prototype.
## Instance methods
_Inherits instance methods from its parent {{jsxref("Function")}}_.
## Specifications
{{Specifications}}
## Browser compatibility
{{Compat}}
## See also
- [`async function*`](/en-US/docs/Web/JavaScript/Reference/Statements/async_function*)
- [`async function*` expression](/en-US/docs/Web/JavaScript/Reference/Operators/async_function*)
- {{jsxref("Function")}}
- {{jsxref("AsyncFunction")}}
- {{jsxref("GeneratorFunction")}}
- {{jsxref("Functions", "Functions", "", 1)}}
|