What rule do you want to change?

func-style

What change do you want to make?

Generate fewer warnings

How do you think the change should be implemented?

A new option

Example code

type Fn = () => undefined

/* eslint func-style: ["error", "declaration"] */

const expression: Fn = function () {}

const arrow: Fn = () => {}


[playground](https://typescript-eslint.io/play/#code=C4TwDgpgBAYgdlAvFAFASiQPigVzgEwgDMBLOCfAKEoHoAqCAZwBszgoi8BjAWkdGYQAXFADaAIggAnKQHsp4gDRRxhLswCGUjcBKy44gLp0a1Lvv5QIADzBSmjPXBHwkHbrv2oMAbygBfMwt2LTkAdxcEZHQsKD9AoA&eslintrc=N4KABGBEBOCuA2BTAzpAXGYBfEWg&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA)

What does the rule currently do for this code?

It reports both expression and arrow should be declared as a function declaration.

What will the rule do after it's changed?

I suggest to add a new option allowTypeAnnotation. If the function style is set to declaration, and allowTypeAnnotation is true, then the rule will not report expression-style functions if the variable declarator has a type annotation.

Participation

• I am willing to submit a pull request to implement this change.

Additional comments

I reported this a while back as typescript-eslint/typescript-eslint#8488. But I understand ESLint core rules now also accept some TypeScript specific options.