8$: Warn on unused arrow expression

[strager]

useEffect(() => {
  // BUG: async arrow function not used.
  async () => {
    const userReviewsForEachAudiobook = await Promise.all(
      reviewsUrlList.map((review) => {
        return fetch(review).then((res) => res.json());
      })
    );
  };
}, [reviewsUrlList]);

[strager]

I think this should be simple. In parse_and_visit_statement, when we parse an expression, and the expression is an arrow function, report a warning.

[singalhimanshu]

I claim this for-hire task. I expect payment after I complete this task. I will email the quick-lint-js team if I am assigned this task.

[singalhimanshu]

@strager which of these should report error_unused_arrow_function:

// 1.
async => {}
async => rhs;
// 2.
let => {}
// 3.
x => {}
// 4.
=> x + y

[strager]

@strager which of these should report error_unused_arrow_function:

1, 2, and 3.

4 should report a different diagnostic (E0105).

[jr-boney]

useEffect(() => {
(async () => {
const userReviewsForEachAudiobook = await Promise.all(
reviewsUrlList.map((review) => {
return fetch(review).then((res) => res.json());
})
);
})();
}, [reviewsUrlList]);

[strager]

@jr-boney I don't see any unused arrow expressions in your code. Are you seeing a bug in quick-lint-js related to your code?