Currently trying to convert a part of the codebase into Flow. While I was tackling with API calls, I have created a hook to abstract the functionality. However when I tried to import it, the function always returned with a later-added any type.

useApi.js

// @flow
import {useState, useEffect} from 'react';

export default function useApi<T>(
    apiCall: (...args: any[]) => Promise<T>,
    initialValue:T[]=[]
): T[] {
    const [data, setData] = useState(initialValue);
    useEffect(() => {
        apiCall().then(setData).catch(console.error);
    }, [apiCall]);
    return data;
}

App.js

import './App.css';
import useApi from './hooks/useApi';
import { getOffers } from './service/Offers';
import { useCallback } from "react";
import Header from "./components/Header";
import Card from "./components/Card";

function App() {
  const getOffersMemo = useCallback(() => getOffers(), []);
  const offers = useApi(getOffersMemo); // type => OfferModel[] | any
  return (//SomeTemplate);
}

export default App;

However when I use export without default keyword it doesn't add any type. What is the reason for this behavior?