You've written a very good and mostly correct hook! ✅ Now let’s break your questions one by one:

1️⃣ Is this writing format ok?

👉 Yes — this format is perfectly fine and commonly used in React hooks.

2️⃣ Can async function be written on top or outside and called from useEffect?

👉 Yes — exactly how you did it:

async function fetchModel(ignore) { ... }
 
useEffect(() => { ... fetchModel(ignore); ... }, []);

✅ This is valid.

3️⃣ Is there any bug?

👉 You do not have a real bug, but one small improvement:

Potential issue: Stale closure or race condition

👉 You are passing ignore as an argument:

fetchModel(ignore);

But since fetchModel is async, the ignore variable might change during the async process, especially if the component unmounts quickly.

👉 A better way is to use a let ignore = false inside the effect and not pass it as an argument — but access it inside the function.

✅ Example improved version:

import { useEffect, useState } from "react";
 
export default function useModel() {
  const [models, setModels] = useState([]);
 
  useEffect(() => {
    let ignore = false;
 
    async function fetchModel() {
      try {
        const response = await fetch("https://image.pollinations.ai/models");
        if (!response.ok) {
          console.log("Failed to Fetch Models");
          return;
        }
        const data = await response.json();
        if (!ignore) {
          setModels(data);
        }
      } catch (error) {
        console.log(error.message);
      }
    }
 
    fetchModel();
 
    return () => {
      ignore = true;
    };
  }, []);
 
  return models;
}

Summary:

✅ Yes, writing format is OK. ✅ You can write async function outside useEffect and call it inside. ⚠️ Minor improvement: avoid passing ignore — better access ignore inside the async function (to avoid subtle bugs). ✅ No major bugs.

If you want, I can also show an even cleaner pattern using AbortController for fetch cancellation — very useful for real apps. Just say if you want to see it. 🚀