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function*

The function* keyword can be used to define a generator function inside an expression.

Syntax

function* [name]([param1[, param2[, ..., 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
The statements which comprise the body of the function.

Description

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

Examples

Using function*

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

let x = function*(y) {
   yield y * y;
};

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
function* 49 12 26 No 36 10
Trailing comma in parameters 58 79 52 No 45 10
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
function* 49 49 26 36 10 5.0
Trailing comma in parameters 58 58 52 43 10 7.0
Server
Node.js
function* 4.0.0
Trailing comma in parameters 8.0.0

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/function*