Iterator helper methods are undefined using reactive proxy

[c-harding]

Vue version

3.5.13

Link to minimal reproduction

https://play.vuejs.org/#eNp9ktFLwzAQxv+VEB+6QemQ6cscgsoe5oOK8zEgpbvVzDQJyaUrjP7vXlpWh257y9139/WXr9nzB2uzOgCf8bkvnLTIPGCw90LLyhqHbM8c5AXKGljLNs5ULKH55E5ooQujvVGQKVOOkiWCy9G4K28qYNBIjz5JNezYCnA0zupcBfB0iPr44vLagGfaYO+SpAeC0eD23+6cYZXbAYadoCH9LEzc/csyxHESpnebT/osKUUqECqrcgSq5pOjgqccPX14I8ts642mf7AXmjHBC1NZqcC9WpQEJviMdUrUcqXM7rnroQuQHvrFFxTfJ/pb38Se4G8OPLgaBB80zF0J2MuL1Qs0dB7EyqyDoukL4jtQaCEy9mOPQa8J+2iuo112L0nq8sMvGgTtD5eKoHGy7eYFp4f1dOHqv7jT7KbbE7qlFD9rcNGTApxmt9n1lLc/l1P2tg==

Steps to reproduce

Call an iterator helper method, e.g. new Set([1,2]).values().some(value => value > 5). This works (in modern browsers, see MDN).

For typescript, this is available in es2024.

Now use a reactive object to do the same (reactive(new Set([1,2])).values().some(value => value > 5)). This should behave the same, but instead undefined is not a function, despite it typechecking in TypeScript.

What is expected?

reactive(new Set(...)) should offer exactly the same interface as new Set(...).

An ideal futureproof solution would be that any method is called through, if it has not been patched.

What is actually happening?

TypeError: undefined is not a function.

In the reproduction link, I have logged two different methods, with and without reactive. When using reactive, undefined is logged instead of the desired method.

System Info

Tested in Firefox 133.0.3 on macOS. Occurs in the playground (see link above).

Any additional comments?

No response

[Bayn-Web]

See this. Vue dropped rest of the function except next.

[c-harding]

Yup, that's definitely the offending code. I suspect this could be fixed with Object.assign(Object.create(Iterator), {…})

[edison1105]

duplicate of #12615