AsyncGeneratorFunction
The AsyncGeneratorFunction object provides methods for async generator functions. 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:
const AsyncGeneratorFunction = async function* () {}.constructor;
AsyncGeneratorFunction is a subclass of {{jsxref("Function")}} .
{{InteractiveExample("JavaScript Demo: AsyncGeneratorFunction", "taller")}}
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
AsyncGeneratorFunctionobject.
- : Creates a new
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
AsyncGeneratorFunctioninstances, the initial value is the{{jsxref("AsyncGeneratorFunction/AsyncGeneratorFunction", "AsyncGeneratorFunction")}}constructor.
- : The constructor function that created the instance object. For
AsyncGeneratorFunction.prototype.prototype- : All async generator functions share the same
prototypeproperty, which isAsyncGenerator.prototype. Each async generator function created with theasync function*syntax or theAsyncGeneratorFunction()constructor also has its ownprototypeproperty, whose prototype isAsyncGeneratorFunction.prototype.prototype. When the async generator function is called, itsprototypeproperty becomes the prototype of the returned async generator object.
- : All async generator functions share the same
AsyncGeneratorFunction.prototype[Symbol.toStringTag]- : The initial value of the
[Symbol.toStringTag]property is the string"AsyncGeneratorFunction". This property is used in{{jsxref("Object.prototype.toString()")}}.
- : The initial value of the
These properties are own properties of each AsyncGeneratorFunction instance.
{{jsxref("AsyncGeneratorFunction/prototype", "prototype")}}- : Used when the function is used as a constructor with the
newoperator. It will become the new object’s prototype.
- : Used when the function is used as a constructor with the
Instance methods
Inherits instance methods from its parent {{jsxref("Function")}} .
Specifications
{{Specifications}}
Browser compatibility
{{Compat}}
See also
async function*async function*expression{{jsxref("Function")}}{{jsxref("AsyncFunction")}}{{jsxref("GeneratorFunction")}}{{jsxref("Functions", "Functions", "", 1)}}