React项目调用Firestore取数失败,报FirebaseError类型错误
解决Firestore获取数据时的"Expected type 'eh', but it was: a function"错误
问题原因
你传入getDocs的membersCollectionRef是一个函数,但getDocs要求参数是Firestore的集合引用(CollectionReference)类型,类型不匹配导致了这个报错。你用useCallback包裹了一个返回集合引用的函数,但调用getDocs时没有执行这个函数来获取实际的引用。
解决方案
方法1:调用函数获取集合引用
在getDocs中执行membersCollectionRef(),拿到实际的集合引用后再传入:
import { useState, useEffect, useCallback } from "react"; import { db } from "../utils/firebase-config"; import { collection, getDocs } from "firebase/firestore"; export default function MemberPage() { const [members, setMembers] = useState([]); const membersCollectionRef = useCallback(() => collection(db, "members"), []); useEffect(() => { const getMembers = async () => { // 调用函数获取集合引用 const data = await getDocs(membersCollectionRef()); setMembers(data.docs.map((doc) => ({ ...doc.data(), id: doc.id }))); }; getMembers(); }, [membersCollectionRef]); return (...); }
方法2:直接在useCallback中返回集合引用(更简洁)
调整useCallback的写法,让membersCollectionRef本身就是集合引用,而不是返回引用的函数:
import { useState, useEffect, useCallback } from "react"; import { db } from "../utils/firebase-config"; import { collection, getDocs } from "firebase/firestore"; export default function MemberPage() { const [members, setMembers] = useState([]); // 直接返回集合引用,不再包裹函数 const membersCollectionRef = useCallback(collection(db, "members"), []); useEffect(() => { const getMembers = async () => { const data = await getDocs(membersCollectionRef); setMembers(data.docs.map((doc) => ({ ...doc.data(), id: doc.id }))); }; getMembers(); }, [membersCollectionRef]); return (...); }
额外优化:无需useCallback的场景
如果你的db实例不会发生变化,甚至可以省略useCallback,直接定义集合引用即可——因为collection返回的引用是稳定的,不会触发不必要的组件重渲染:
import { useState, useEffect } from "react"; import { db } from "../utils/firebase-config"; import { collection, getDocs } from "firebase/firestore"; export default function MemberPage() { const [members, setMembers] = useState([]); // 直接定义集合引用 const membersCollectionRef = collection(db, "members"); useEffect(() => { const getMembers = async () => { const data = await getDocs(membersCollectionRef); setMembers(data.docs.map((doc) => ({ ...doc.data(), id: doc.id }))); }; getMembers(); }, [membersCollectionRef]); return (...); }
内容的提问来源于stack exchange,提问作者Adrian Grzelka
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