允许通知但权限 === "授予"返回 false

Question

我正在为 JavaScript 设置一个 Firebase 客户端。当要求通知权限时，我允许它，但它仍然返回false.

firebase.initializeApp(firebaseConfig);
// Retrieve Firebase Messaging object.
const messaging = firebase.messaging();
//Request permission to receive notifications
messaging.requestPermission().then((permission) => {
if (permission === 'granted') {
console.log('Notification permission granted.');
// TODO(developer): Retrieve an Instance ID token for use with FCM.
// ...
} else {
console.log('Unable to get permission to notify.');
}
});

当我单击允许时，我在控制台中收到以下内容"无法获得通知权限"。

Answer 1

根据文档：

如果授予权限，则承诺将解析。否则，承诺将被拒绝并显示错误。

因此，与其检查传递的参数，不如检查承诺是解析还是拒绝：

messaging.requestPermission().then(() => {
console.log('Notification permission granted.');
// TODO(developer): Retrieve an Instance ID token for use with FCM.
// ...
}).catch((err) => {
console.log('Unable to get permission to notify.');
});

话虽如此，根据文档，requestPermission()已被弃用，应替换为Notification.requestPermission().那个看起来更像你尝试的方式：

Notification.requestPermission().then((permission) => {
if (permission === 'granted') {
console.log('Notification permission granted.');
// TODO(developer): Retrieve an Instance ID token for use with FCM.
// ...
} else {
console.log('Unable to get permission to notify.');
}
});