Question

我正在尝试创建Google身份验证，但我将var provider = new firebase.auth.GoogleAuthProvider();复制到我的JavaScript中，它一直告诉我Uncaught ReferenceError: firebase is not defined。

这是我的代码：

var provider = new firebase.auth.GoogleAuthProvider();

function signin(){

  firebase.auth().signInWithPopup(provider).then(function(result) {

  var token = result.credential.accessToken;
  var user = result.user;

}).catch(function(error) {

  var errorCode = error.code;
  var errorMessage = error.message;
  var email = error.email;
  var credential = error.credential;

}); 
}

Answer 1

You are getting this error because firebase variable has not been instantiated and initialized on the page on which you are running the code. To do so you need to -

Include the relevant scripts-

<script src="https://www.gstatic.com/firebasejs/4.1.3/firebase.js"></script> <script src="https://www.gstatic.com/firebasejs/4.1.3/firebase-auth.js"></script>

firebase.js contains the variable firebase representing your firebase app. firebase-auth.js contains the firebase.auth library which your code is using.

Initialize your app using -

var config = {
    apiKey: "<API_KEY>",
    authDomain: "<PROJECT_ID>.firebaseapp.com",
    databaseURL: "https://<DATABASE_NAME>.firebaseio.com",
    storageBucket: "<BUCKET>.appspot.com",
    messagingSenderId: "<SENDER_ID>",
};

firebase.initializeApp(config);

To learn more refer - https://firebase.google.com/docs/web/setup

Answer 2

Firebase的一个常见陷阱会导致此错误，如果脚本在Firebase之前加载。例如，当使用Firebase Hosting时，它们将创建以下标签：

  <script defer src="/__/firebase/6.0.2/firebase-app.js"></script>
  ...
  <script defer src="/__/firebase/init.js"></script>

然后您还需要使用defer加载脚本

  <script defer src="js/app.js"></script>

未捕获的ReferenceError：未定义firebase

2 个答案: