Enforce the spacing around the * in generators (generator-star-spacing)

Generators are a new type of function in ECMAScript 6 that can return multiple values over time. These special functions are indicated by placing an * after the function keyword.

Here is an example of a generator function:

function* generator() {
    yield "44";
    yield "55";
}

This is also valid:

function *generator() {
    yield "44";
    yield "55";
}

This is valid as well:

function * generator() {
    yield "44";
    yield "55";
}

To keep a sense of consistency when using generators this rule enforces a single position for the *.

Rule Details

This rule aims to enforce spacing around * of the generator function.

The rule takes one option, an object, which has two keys before and after having boolean values true or false.

before aims to spacing between the * and the function keyword. If it’s true, space is enforced, otherwise space is disallowed.

In object literal shorthand methods, spacing before the * is not checked, as they lack a function keyword.
after aims to spacing between the * and the function name. If it’s true, space is enforced, otherwise space is disallowed.

In anonymous function expressions, spacing between the * and the opening parenthesis is not checked. This is checked by the space-before-function-paren rule.

The default is {"before": true, "after": false}.

"generator-star-spacing": [2, {"before": false, "after": true}]

And the option has shorthand as a string keyword:

{"before": true, "after": false} → "before"
{"before": false, "after": true} → "after"
{"before": true, "after": true} → "both"
{"before": false, "after": false} → "neither"

"generator-star-spacing": [2, "after"]

When using {"before": true, "after": false} this placement will be enforced:

function *generator() {}

var anonymous = function *() {};

var shorthand = { *generator() {} };

When using {"before": false, "after": true} this placement will be enforced:

function* generator() {}

var anonymous = function*() {};

var shorthand = { * generator() {} };

When using {"before": true, "after": true} this placement will be enforced:

function * generator() {}

var anonymous = function *() {};

var shorthand = { * generator() {} };

When using {"before": false, "after": false} this placement will be enforced:

function*generator() {}

var anonymous = function*() {};

var shorthand = { *generator() {} };

To use this rule you must set the generators flag to true in the ecmaFeatures configuration object.

Enforce the spacing around the * in generators (generator-star-spacing)

Rule Details

When Not To Use It

Further Reading

Version

Resources