send push notification with vue-native and expo - vue.js

Question

I'm new to vue-native and vuejs and want to make an application with them. I want to add push notification to the app. I use this tutorial for add push notification and test it but I get this Error
Error in created hook: "TypeError:
this.registerForPushNotificationsAsync is not a function. (In
'this.registerForPushNotificationsAsync()',
'this.registerForPushNotificationsAsync' is undefined)"
I add this block of code in my project like this in app.vue file
<template>
<view class="container">
<text class="text-color-primary">{{JSON.stringify(notification.data)}}</text>
</view>
</template>
<script>
export default {
data: function() {
return {
notification: {}
};
},
created: function() {
this.registerForPushNotificationsAsync();
this._notificationSubscription = Notifications.addListener(
this._handleNotification
);
},
methods:{
_handleNotification: function(notification) {
this.notification = notification;
},
registerForPushNotifications: async function() {
const { status: existingStatus } = await Permissions.getAsync(
Permissions.NOTIFICATIONS
);
let finalStatus = existingStatus;
// only ask if permissions have not already been determined, because
// iOS won't necessarily prompt the user a second time.
if (existingStatus !== "granted") {
// Android remote notification permissions are granted during the app
// install, so this will only ask on iOS
const { status } = await Permissions.askAsync(
Permissions.NOTIFICATIONS
);
finalStatus = status;
}
// Stop here if the user did not grant permissions
if (finalStatus !== "granted") {
return;
}
// Get the token that uniquely identifies this device
Notifications.getExpoPushTokenAsync().then(token => {
console.log(token);
});
}
}
};
</script>
where i go wrong?