Add parent child whenever onchild created cloud function real time database - node.js

Question

Here I have code that trigger ref /tugas_course/{course_id}/{tugas_id} whenever child added will send notification to the android device. It already doing really well. But I want to add one more function inside it, I want to add child outside this ref called flag_tugas and will be populate with flag_tugas-course_id-tugas_id-user.uid: "o". I dont know how to add it, because the return value already take it all and how to get users id in cloud function.
export const onNotifTugas = functions.database.ref('/tugas_course/{course_id}/{tugas_id}')
.onCreate((snapshot, context) =>{
const course_id = context.params.course_id;
const tugas_id = context.params.tugas_id;
console.log(`New Message ${course_id} in ${tugas_id}`);
return admin.database().ref('/tugas/' + tugas_id +'/').once('value').then(snap => {
const tugasData = snap.val();
const notifDataSend = { // buat structure data json dgn nama const notifDataSend untul cloud messaging
data: {
data_type: "tugas",
title: "Anda mendapatkan notifikasi baru..", // data bebas (key, value)
body: `Tugas ${tugasData.nama_tugas} baru`, // chatId = const chatId
sound: "default"
}
};
console.log(`data yang dikirim `);
return admin.messaging().sendToTopic(course_id, notifDataSend)
.then(function(response) {
console.log("Successfully sent message:", response);
})
.catch(function(error) {
console.log("Error sending message:", error);
});
}).catch(error => {
console.log(error);
})
});
}
Actually adding the new child under eclassapp
Really thanks for your time and answer..

Answer 1

I am not sure to fully understand where you want to add the timestamp in your node tree (under /tugas_course/{course_id}/{tugas_id}/new_child or under /tugas_course/{course_id}/{tugas_id}) but the following code will work for adding a timestamp value right under /tugas_course/{course_id}/{tugas_id}. If you need you can change the value of ref to write the timestamp where you want.
exports.onNotifTugas = functions.database
.ref('/tugas_course/{course_id}/{tugas_id}')
.onCreate((snapshot, context) => {
const ref = snapshot.ref;
const ts = admin.database.ServerValue.TIMESTAMP;
return ref.update({
date_time: ts
});
});
Note however that you don't need a Cloud Function to add a timestamp from the server, see https://firebase.google.com/docs/reference/js/firebase.database.ServerValue
So in your case you would do something like:
var tugaRef = firebase.database().ref("/tugas_course/course_id/tugas_id");
tugaRef.push({
foo: bar, //Other data of your 'tugas' object
createdAt: firebase.database.ServerValue.TIMESTAMP
})