响应本机Firebase DataSnapshot [英] React Native Firebase DataSnapshot

问题描述

我正在尝试使用以下代码在我的React Native应用中实现Firebase:

I'm trying to implement firebase into my React Native app with the following code:

import * as firebase from 'firebase'
var fireBaseconfig = {
apiKey: "MY KEY",
authDomain: "MY DOMAIN",
databaseURL: "MY URL",
storageBucket: "MY BUCKET",
};
var firebaseApp = firebase.initializeApp(fireBaseconfig);
var rootRef = firebase.database().ref;
var query = rootRef.ref("items");
 query.once("value")
   .then(function(snapshot) {
   snapshot.forEach(function(childSnapshot) {
   var key = childSnapshot.key;
   var childData = childSnapshot.val();
  });
});

我收到错误消息:未定义不是函数(正在评估'rootRef.ref("items"))

I am getting the error: "undefined is not a function (evaluating 'rootRef.ref("items")')

我遵循了包括官方文档在内的一些教程，但尚未找到解决方案.我在React Native上使用正确的语法吗?

I have followed several tutorials including the official documentation and haven't been able find a solution to this. Am I using the right syntax for React native?

推荐答案

在firebase.database().ref中，ref是一个函数，因此应为ref().

In firebase.database().ref, ref is a function so should be ref().

由于返回了Reference，因此您必须调用child()来生孩子.

Since that returns a Reference, you have to call child() to get a child.

所以:

import * as firebase from 'firebase'
var fireBaseconfig = {
apiKey: "MY KEY",
authDomain: "MY DOMAIN",
databaseURL: "MY URL",
storageBucket: "MY BUCKET",
};
var firebaseApp = firebase.initializeApp(fireBaseconfig);
var rootRef = firebase.database().ref();
var ref = rootRef.child("items");
ref.once("value").then(function(snapshot) {
   snapshot.forEach(function(childSnapshot) {
     var key = childSnapshot.key;
     var childData = childSnapshot.val();
   });
});

我还重命名了query变量，因为它实际上不是查询，而只是对子位置的另一个引用.

I also renamed the query variable, because it's actually not a query but just another reference to a child location.

这篇关于响应本机Firebase DataSnapshot的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！