The function*
keyword can be used to define a generator function inside an expression.
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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
Specification |
---|
ECMAScript (ECMA-262) The definition of 'function*' in that specification. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
function* | Chrome Full support 49 | Edge Full support 12 | Firefox Full support 26 | IE No support No | Opera Full support 36 | Safari Full support 10 | WebView Android Full support 49 | Chrome Android Full support 49 | Firefox Android Full support 26 | Opera Android Full support 36 | Safari iOS Full support 10 | Samsung Internet Android Full support 5.0 | nodejs Full support 4.0.0 |
Trailing comma in parameters | Chrome Full support 58 | Edge Full support 79 | Firefox Full support 52 | IE No support No | Opera Full support 45 | Safari Full support 10 | WebView Android Full support 58 | Chrome Android Full support 58 | Firefox Android Full support 52 | Opera Android Full support 43 | Safari iOS Full support 10 | Samsung Internet Android Full support 7.0 | nodejs Full support 8.0.0 |
Legend
- Full support
- Full support
- No support
- No support
See also
function*
statementGeneratorFunction
object- The Iterator protocol
yield
yield*
Function
objectfunction
statementfunction
expression- Functions and function scope