function* expression - JavaScript 编辑

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

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

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

BCD tables only load in the browser

See also

• function* statement
• GeneratorFunction object
• The Iterator protocol
• yield
• yield*
• Function object
• function statement
• function expression
• Functions and function scope