Not really, at best it's a verbose and limited subset. https://github.com/tc39/p...

culi · 2025-12-14T22:38:54 1765751934

It's certainly more verbose but certainly not a limited subset. You can copy paste any typescript Type or Interface in a jsdoc @typedef. As I stated in the article, it's still the TypeScript language service that's analyzing either JSDoc-defined types or TypeScript defined types. It's typescript all the way down

But JSDoc lets you do pretty much everything that isn't a runtime feature of TypeScript (e.g. enums, namespaces, etc). Even generic slots are supported

g947o · 2025-12-14T23:27:51 1765754871

You just haven't worked in a complex enough project yet.

I found several limitations and already opened several issues on github.

efortis · 2025-12-14T22:33:14 1765751594

Although it's more verbose, it makes code less dense because it lives outside the function parameters.

Also, it's not a super limited subset. For instance, you can write types in .d.ts the IDE uses those types in jsdoc out of the box.

epolanski · 2025-12-14T22:40:05 1765752005

The list of things jsdoc cannot do is long but a simple example is overloading, you cannot express this[1] in jsdoc, and if you need to reference .d.ts files you're back at using TypeScript, so the point of JSDoc was...?

If you need precise return typing, conditional types, literal values, etc, you aren't going far if anywhere with JSDoc.

[1] https://shorturl.at/pg5dL

efortis · 2025-12-14T23:42:39 1765755759

There a few points in favor of TS types in jsdoc (in order):

1. not having to type everything (many types are not helpful)

2. makes code less dense (and they can be rendered in HTML) https://x.com/efortis/status/1989776568676221137

3. not needing a compiler (browsers don't support TS)

I think the main jsdoc caveat is around private types.

About 1, IDK if there’s a way to set up TS for that.

g947o · 2025-12-14T23:34:17 1765755257

This specific one is actually supported since TypeScript 5.0:

https://devblogs.microsoft.com/typescript/announcing-typescr...

But not properly documented (https://www.typescriptlang.org/docs/handbook/jsdoc-supported...), which shows how much Microsoft neglects JS + JSDoc workflow. Github issues have been created a long time ago, but nothing has been done so far. Apparently Microsoft is too busy with their AI slop to work on actually useful stuff.