Class generics not evaluated properly in JSDoc

🔎 Search Terms

jsdoc generics

🕗 Version & Regression Information

This is the behavior in every version I tried (i.e. at random from 3.6.3 to nightly), and I reviewed the FAQ for entries about jsdoc and generics

⏯ Playground Link

https://www.typescriptlang.org/play?ts=5.4.0-dev.20231205&filetype=js#code/PQKhAIAEBcFMFsAOAbAhncAVcJgCgBjNAZ2PABEB7ecAbz3EfFAhgE9FY6B5AIwCtYBaAB5i0AE4BLAHYBzADRYAfAF8c+JuBmUAJrGIAhNgEld4ALx1VAbgZM5saAGEAFlOS6JsGQAoAlHTe0ACuEjLg0O7EAHQ6+kamuqp4KXgsUNAcXLRU8CIyIfC8sBJqGoSUMuLaelxWMrAA7hTUAXYEVTUE7p7eEQ11MY4uvV4+7UA

💻 Code

(not working): TypeScript in JSDoc (playground link)

/** @template T */
class Dom {
    /** @type {Object<string, T>} */
    nodesById = {};
    getChildren() {return this.nodesById}
}

/** @type {Dom<number>} */
const node = new Dom();
const children = node.getChildren(); // type is {[id: string]: T}

(working): TypeScript (playground link)

class Dom<T> {
    nodesById: {[id: string]: T} = {};
    getChildren() {return this.nodesById}
}

const node = new Dom<number>();
const children = node.getChildren(); // type is {[id: string]: number}

🙁 Actual behavior

With TypeScript in JSDoc, children has the type {[id: string]: T}, i.e. T is not resolved, although node has the type Dom<number>.

🙂 Expected behavior

With TypeScript, children has the type {[id: string]: number}, i.e. T is taken correctly from Dom<number>. The same is expected for TypeScript in JSDoc.

Additional information about the issue

Obviously, this is just a minimal working example. We have a large legacy codebase where we introduce TypeScript gradually via JSDoc comments (a nuke-everything TypeScript rewrite would not be feasible).