javascript - 如何从 Firebase 数据快照中获取 key ？

Question

我可以使用电子邮件地址查询我的 users 数组并返回用户的帐户信息:

users.orderByChild('email').equalTo(authData.user.email).once('value').then(function(snapshot) {
        console.log(snapshot.val());
        console.log(snapshot.key); // 'users'
        console.log(snapshot.child('email').key); 'email'
        ...

如何获取 key (-KiBBDaj4fBDRmSS3j0r)。 snapshot.key 返回users。 snapshot.child('email').key 返回 email。该 key 似乎不是子项，即它似乎位于 users 和 email 之间。

Answer 1

你可以这样做:

var key = Object.keys(snapshot.val())[0];

引用号:https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/keys

The Object.keys() method returns an array of a given object's own enumerable properties, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).