Create TypeScript definitions

[vankop]

There is a killer feature for stylelint in TypeScript 3.7 - now it possible to create declaration file from JS https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#--declaration-and---allowjs

Blocked by: #4245

[hudochenkov]

I don't think we need a separate issue for this. Upgrade would be handled as with any other dependency.

[vankop]

This issue was not about upgrade at first place, It is about creating definitions =)

[hudochenkov]

Then rename it and explain a little bit more in the first comment :)

[jeddy3]

This is neat. It's great to see JSDocs TypeScript getting some love.

[jeddy3]

With #4245 now closed, I'm removing the '"blocked" label.

[hudochenkov]

Currently it's blocked by #4505

[ybiquitous]

Currently it's blocked by #4505

We are using TypeScript 3.7 now,

stylelint/package.json

Line 116 in c63a45f

"typescript": "^3.7.5"

and we will be able to use TypeScript 3.8 soon via #4626! 😄

[tyankatsu0105]

Hi.
I have a question.
I just found types.
But what for?
At least currently, the types have not been released.

[hudochenkov]

@tyankatsu0105 we use TypeScript to avoid bugs in our code

stylelint/package.json

Line 44 in 6cfea29

"lint:types": "tsc",

We don't use TypeScript language, but JSDoc, which is supported by TypeScript type checker.

[tyankatsu0105]

@hudochenkov
I see. So these types are not for creating stylelint plugin or something with stylelint but for supporting to develop stylelint self, right?

[hudochenkov]

Right. But we want to expose them in future, so plugin developers could use them. That's why we have this issue.

[tyankatsu0105]

But we want to expose them in future, so plugin developers could use them

Awesome!!!
I created stylelint plugin with TypeScript.
https://github.com/tyankatsu0105/stylelint-typescript.
I was worried because @types/stylelint seemed like this wasn't already being maintained.

Thanks for the reply @hudochenkov :)

[glen-84]

I tried this now, and most of the declaration files appear to be generated, but there are at least two issues:

#1

lib/utils/parseCalcExpression/parser.js:383:13 - error TS9005: Declaration emit for this file requires using private name 'Parser'. An explicit type annotation may unblock declaration emit.

383 var parser = (function () {
~~~

Found 1 error.

This looks like a generated file, so it probably can't be edited.

Possibly related to microsoft/TypeScript#37832 or microsoft/TypeScript#38382.

#2

Multiple declaration files have code like this:

export = _exports;

... with the error: An export assignment cannot be used in a module with other exported elements.

I couldn't find an existing TypeScript issue regarding this error, but other projects have run into this as well it seems.

---

You can test it yourself by adding the following to tsconfig.json:

        "declaration": true,
	"emitDeclarationOnly": true,
	"outDir": "types-new"

(and optionally removing "noEmit": true, which is not needed)

Then run npx tsc.

[Phillip9587]

Any progress on this? It really sucks that there are only outdated types available. I may help if someone describes the current status to me...

[jeddy3]

I may help if someone describes the current status to me...

The last attempt (#4399 (comment)) to do this was a year ago and some issues were encountered. Things may have improved since then. So, if you've time you're welcome to look into it. It would be amazing to resolve as TypeScript usage has exploded.

[glen-84]

Apart from the 2 issues previously mentioned (which still exist – perhaps related to microsoft/TypeScript#41672), there is also an issue in lib/formatters/index.js, where there is a missing argument (x6).

lib/formatters/index.js:6:11 - error TS2554: Expected 1 arguments, but got 0.

6  compact: importLazy(() => require('./compactFormatter'))(),
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  node_modules/import-lazy/index.d.ts:24:5
    24 ): (moduleId: string) => T;
           ~~~~~~~~~~~~~~~~
    An argument for 'moduleId' was not provided.

[Phillip9587]

@jeddy3 @glen-84 Would migrating Stylelint to Typescript be an option or are there any reasons you haven't done that yet?

[ybiquitous]

@glen-84 About #4399 (comment), I've opened the issue to import-lazy: sindresorhus/import-lazy#19

But, to fix the TS error, it seems that we could just specify a module ID as below:

-	compact: importLazy(() => require('./compactFormatter'))(),
+	compact: importLazy(() => require('./compactFormatter'))('compactFormatter'),

[glen-84]

@ybiquitous Is stylelint even being bundled in the first place?

[ybiquitous]

@glen-84 Do you mean stylelint provides a bundle version for browsers?
If so, the answer perhaps is “no” (see also #4796).

I think this lazy loading is for performance, as I see #4278.

[glen-84]

@glen-84 Do you mean stylelint provides a bundle version for browsers?

Yes. It looks like @jeddy3 changed the code here.

It could probably be reverted to the standard usage of import-lazy until a decision is made WRT bundling, but there are other issues with the TypeScript build anyway.

[marcfallows]

Given types exist in https://github.com/stylelint/stylelint/tree/master/types/stylelint, couldn't these be exposed in the files in package.json so consumers of the npm package can use them?

[ybiquitous]

I've requested to remove the @types/stylelint package: DefinitelyTyped/DefinitelyTyped#57472