A page on the docs site to show how to create a hook that loads data form an external source such that there would be no gap

Let's say I want to create a hook called useSettings. This hook will load settings once from an API and cache the data.

This is a sample code:

import {
    useEffect,
    useState,
} from "react"

let cache

const useSettings = () => {

    const [settings, setSettings] = useState(cache || [])

    useEffect(() => {
        if (cache) return
        callApi("/settings")
            .then(data => {
                setSettings(data)
                cache = data
            })
    }, [])

    const getSetting = (key, fallback) => {
        const setting = settings.find(i => i.key === key)
        if (!settings) {
            return fallback
        }
        return setting.value
    }

    return {
        getSetting
    }
}

export default useSettings

This works fine when the settings are loaded. But when a component uses this hook, there is an unpredictable time at the beginning when the settings are not loaded yet, and they get the fallback value.

I searched the docs and navigated the menu items. I could not find a page as a guide on how to remove that gap.

Please add a page for this purpose. Explain what is the react's official way to solve this problem. Explain how we can make sure that when we call a hook, we are guaranteed to get the data.

首先查看現有的 React 文件和 issue 中的 useSettings 範例，以確定應在哪裡加入有關載入外部資料的指引。完成後的頁面應說明避免初始資料缺失的官方方式，以及 hook 如何在消費者使用資料之前保證資料可用。