V8 has a number of parser tests, for example, as well as some in their mjsunit suite: [e.g.](https://chromium-review.googlesource.com/c/v8/v8/+/856937) `export default ()`. SpiderMonkey too. (This will require confirming they have compatible licenses.)
V8 has a number of parser tests, for example, as well as some in their mjsunit suite: e.g.
export default ().SpiderMonkey too.
(This will require confirming they have compatible licenses.)