Add Class Private Identifier

[DawChihLiou]

Include Private Class Member (# name)

Hi Maintainers👋

I would like to make a modification for private class members. ECMA2022 standardized the private identifier #. It marks class members as private.

Additional Section:

• 9.8 Class members should use # to mark them as private members.

Modified Section:

• 23.4 Do not use trailing or leading underscores.

References:

• MDN - Private class features
• ECMAScript 2022 Language Specification
• TC39 Proposal - Private methods and getter/setters for JavaScript classes
• TC39 Proposal - Class field declarations for JavaScript

[ljharb]

This isn't something the guide can support until babel-preset-airbnb transforms them, and until eslint fully supports linting them with ecmaVersion 2022, which I don't think it quite does yet.

[DawChihLiou]

This isn't something the guide can support until babel-preset-airbnb transforms them, and until eslint fully supports linting them with ecmaVersion 2022, which I don't think it quite does yet.

I did some research and found out that ESLint seems to lint private class member since v8.1.0.

[ljharb]

That’s great - but our eslint config still supports eslint 7, so we wouldn’t be able to recommend using private fields (which are great) until we drop eslint < 8.1.

[DawChihLiou]

Understood. Thanks for taking the time:)

[ljharb]

@Jassi10000 while that's technically true, it's not that important until the PR is ready to be merged - and it's something maintainers can often take care of.