Rule proposal: `prefer-private-class-fields`

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields

Prefer private fields over the convention of underscore prefixed names.

This feature requires Node.js 12, so we cannot add it to the recommended preset until April 2021 (date of Node.js 10 obsoletion).

Does ESLint support this feature yet?

Fail

class Foo {
	static _PRIVATE_STATIC_FIELD

	_privateField

	_privateMethod() {
		return 'hello world'
	}
}

Pass

class Foo {
	static #PRIVATE_STATIC_FIELD

	#privateField

	#privateMethod() {
		return 'hello world'
	}
}

[sindresorhus]

@fisker I would argue having to use a _ prefix to pseudo hide properties/methods is also awkward. I don’t think lack of destructuring is awkward enough to not use private fields. It’s just a minor inconvenience. The proposal-destructuring-private thing will probably not land in Node.js until Node.js 20 at the earliest, which means packages will not be able to use it until 2025.

[fregante]

No longer blocked