Enforce spacing around the * in yield* expressions (yield-star-spacing)

The --fix option on the command line can automatically fix some of the problems reported by this rule.

Rule Details

This rule enforces spacing around the * in yield* expressions.

To use this rule you either need to use the es6 environment or set ecmaVersion to 6 in parserOptions.

Options

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

• before enforces spacing between the yield and the *. If true, a space is required, otherwise spaces are disallowed.

• after enforces spacing between the * and the argument. If it is true, a space is required, otherwise spaces are disallowed.

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

"yield-star-spacing": ["error", {"before": true, "after": false}]

The option also has a string shorthand:

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

"yield-star-spacing": ["error", "after"]

Examples

after

Examples of correct code for this rule with the default "after" option:

/*eslint yield-star-spacing: ["error", "after"]*/
/*eslint-env es6*/

function* generator() {
  yield* other();
}

before

Examples of correct code for this rule with the "before" option:

/*eslint yield-star-spacing: ["error", "before"]*/
/*eslint-env es6*/

function *generator() {
  yield *other();
}

both

Examples of correct code for this rule with the "both" option:

/*eslint yield-star-spacing: ["error", "both"]*/
/*eslint-env es6*/

function * generator() {
  yield * other();
}

neither

Examples of correct code for this rule with the "neither" option:

/*eslint yield-star-spacing: ["error", "neither"]*/
/*eslint-env es6*/

function*generator() {
  yield*other();
}

When Not To Use It

If your project will not be using generators or you are not concerned with spacing consistency, you do not need this rule.

Further Reading

• Understanding ES6: Generators

Version

This rule was introduced in ESLint 2.0.0-alpha-1.

Resources

• Rule source
• Documentation source