Shouldn't typescript use this line regardless of the actual file it's going to import? https://github.com/hapijs/hoek/blob/master/package.json#L12

Reading the article, wouldn't it work having import and require as separate objects like in the last part?

Well, I couldn't reproduce your issue with the condition you provided, and some typescript fixes were done a long while ago in 11.0.4, I see in your issue you're still using 11.0.2, could you try upgrading?

Thank you; I failed to realize I was out of date.

11.0.4 fixes the specific compiler error I was encountering, but the "Masquerading as CJS" issue reported by Are the Types Wrong still exists.

To reproduce:

1. Set up a TypeScript project as ESM (i.e., package.json "type": "module"), with tsconfig.json "module": "NodeNext", "moduleResolution": "NodeNext".
2. In a .ts file, use a default import of Hoek: import Hoek from "@hapi/hoek";

TypeScript will compile without errors, but Node will throw an error at runtime:

import Hoek from "@hapi/hoek";
       ^^^^
SyntaxError: The requested module '@hapi/hoek' does not provide an export named 'default'

You could fix this by using separate import and require objects, as in the last example of Masquerading as CJS, but the import and require options would still need to refer to separate .d.ts files. (If I understand correctly, this is because TypeScript needs to know whether a given .d.ts file refers to CommonJS or ESM, and it determines that by working backwards from the file extension (.d.ts or .d.cts or .d.mts) instead of remembering how it worked forward from an import or require object.) If the separate .d.mts file is added, then the new types line isn't needed, because TypeScript can resolve .d.ts using its normal rules.

(I'll also note that this isn't a huge issue - you can avoid it via import * from Hoek from "@hapi/hoek". It mainly depends on how much you care about catching errors at compile-time vs. runtime and how much you care about keeping Are the Types Wrong happy - I'm starting to care about Are the Types Wrong for my own work, because I'm relying on it as I try to work through type errors in my projects' dependencies.)