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
nameOptional- The function name. Can be omitted, in which case the function is anonymous. The name is only local to the function body.
paramNOptional- 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
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.
Update compatibility data on GitHub
| 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*statementGeneratorFunctionobject- The Iterator protocol
yieldyield*Functionobjectfunctionstatementfunctionexpression- Functions and function scope