Missing rule: typescript-eslint/type-annotation-spacing

[JoshuaKGoldberg]

Missing rule: typescript-eslint/type-annotation-spacing

[bradzacher]

I purposely did not include any of our rules in the list because I wanted to keep the core issue focused on core.

There's defs a few of our rules that can come over too!

[bradzacher]

If they want they could publish it as a separate package within this project - up to them. But as a 3rd party plugin I don't know if it really needs to be split out.

We as the typescript-eslint maintainers have long wanted to remove these formatting rules from our project as we have not maintained them for many years. If this project is happy to get behind the ownership of stylistic then it's probably a great home for them!

[antfu]

Do you have a rule in mind that is:

• Stylistic
• Type-aware
• Works also for JS

So that we could discuss more specifically.

---

For type-annotation-spacing, such "TS-only" + "AST-only" rules look ok to have in this repo, as:

• The name indicates it's type-specific, which doesn't exist in JS. The scope is clear
• It listens to TS AST Nodes, so the rule will only functionally on a TS file and bypass in JS: https://github.com/typescript-eslint/typescript-eslint/blob/066ccf75d126df22a1792d3de3d1e3dd28904db1/packages/eslint-plugin/src/rules/type-annotation-spacing.ts#L274-L281

[ljharb]

I'm not sure how much it makes sense to have type-aware rules in this more general plugin/org. Has that been decided already?

[bradzacher]

We probably won't be migrating over any type-aware rules. Rules like this are purely-syntactic checkers.

The thinking is that this rule should support both JS and TS syntaxes. So it'll be the one-stop-shop for stylistic rules rather than us forking them in typescript-eslint to support TS.

[ljharb]

I think that when a rule can be extended to support TS syntax, that makes perfect sense - but if there's a rule that's only useful for a TS user, then that seems better left to a TS-specific plugin.

[antfu]

#25 (comment)

For type-annotation-spacing itself, it's already been included, as I see you put a warning for it on the docs (as type: layout). I am happy to have it maintained here.

For type-aware rules, I think it would be indeed out-of-scope of ESLint Stylistic.

[ljharb]

(i should clarify; a type-aware rule that works for regular JS seems fine to me; it's a rule that only applies to TS that i'm questioning)

[ljharb]

#25 is TS-only, for example.

[antfu]

Closing as type-annotation-spacing is included. For more discussions about what rules to include, please refer to #26