Javascript 上下文Api firestore

我创建了一个上下文，以便能够在Firestore中Crud我的Categories集合，但是我找不到一种方法来关注getCategories（）函数中的更改。起初创建了一个无限循环，但经过几次尝试后，我能够修复它。现在，在上下文中，如果您正确调用firestore数据，但希望将其发送到我使用上下文的组件，则无法读取数据

函数getCategories in context.js

        .
        .
        .
        const getCategories = (dispatch) => async () => {
            return ref.onSnapshot((querySnapshot) => {
                const data = []
                querySnapshot.forEach(doc => {
                    const { name } = doc.data()
                    data.push({
                        id: doc.id,
                        name
                    })
                })
                console.log('context ',data) //prints correctly
                dispatch({
                    type: 'getCategories',
                    payload: data
                });
            });

        }
        .
        .
        .

Home.js

        .
        .
        .
            const { categoriesState, getCategories } = useContext(CategoriesContext);
            const { categories } = categoriesState;
            const [categoriesData, setCategoriesData] = useState(categories);


            useEffect(() => {
                console.log('Cate statee: ', categories) //print [] which is the initial state of the context
                getCategories()
                console.log('Cate stateHome : ', categoriesData) //print [] which is the initial state of the context
            }, []);
        .
        .
        .