fix: fix marked types

[UziTech]

Marked version: 10.0.0

Description

Fix marked and marked.parse types. async: false could still return a Promise<string> if an extension sets async: true.

• Fixes marked.parseInline() returns string | Promise<string> even when { async: false } #3101

Contributor

• Test(s) exist to ensure functionality and minimize regression (if no tests added, list tests covering this PR); or,
• no tests required for this PR.
• If submitting new feature, it has been documented in the appropriate places.

Committer

In most cases, this should be a different person than the contributor.

• CI is green (no forced merge required).
• Squash and Merge PR following conventional commit guidelines.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
marked-website	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Nov 22, 2023 5:17am

[crystalfp]

Well, with version 11 I have to cast the result to string to have it works:

marked.parse(markdown, {gfm: true, async: false}) as string).replaceAll(...)

Never needed before.

[UziTech]

Yes but it is actually correctly typed now. Before it would be typed as a string even though it could return a Promise.

It would be great if typescript provided a way to return the type based on marked.defaults.async. But as far as I know typescript doesn't have a feature to do that.

[crystalfp]

Ah, this explain everything and I'm happy with the cast solution.
Other possibility, instead of relying on "async" option, is to provide two different entry points like fast-glob does: fglob(): Promise<string[]> and fglob.sync(): string[].
Anyway, thanks for clarifying the issue.
mario

[SupremeVoid]

Yes but it is actually correctly typed now. Before it would be typed as a string even though it could return a Promise.

It would be great if typescript provided a way to return the type based on marked.defaults.async. But as far as I know typescript doesn't have a feature to do that.

How about using a conditional type?

type ParseType<T> = T extends { async: true } ? Promise<string> : string;

function parse<T extends MarkedOptions>(src: string, options?: T): ParseType<T> {}

const string = parse('SomeSrc'); // this returns a string
const string2 = parse('SomeSrc', {async: false});  // this still returns a string
const string3 = parse('SomeSrc', {async: true});  // this returns a Promise<string>