Retrieving data on firebase having child key uid (javascript) - javascript

I am struggling how to retrieve data from firebase having a child key, such as uid.
here is the structure of my firebase.
Currently I am making an admin panel which can read the order placed by each user and render it through flatlist in react native, but it seems that I can't access their order because every time the user places an order it is stored on their unique User.id
I don't know how to make a reference to the User.id child like firebase.database().ref(orders/${AllUserId}/products)

You can use forEach loop to fetch ids and can get values as so
firebase.database().ref('order').on('value', (snapshot) => {
snapshot.forEach((child) => {
uid = child.key; // gives uid1
child.forEach((snap) =>{
var id = snap.key; // first iteration gives uid2
firebase.database().ref('order/'+uid+'/'+id).on('value', (snapchild) => {
snapchild.forEach((snapshotchild) =>{
console.log(snapshotchild.val());
});
});
});
});
});
This could be more insightful.

Related

How to retrieve nested data using Javascript (Firebase Realtime Database)?

I want to retrieve the data from donation and display it in a table. I was able to retrieve the user data from Users and displayed it on a table. But now I don't know how I will be able to retrieve the data from donation.
This is my database structure in Firebase. Note: All of the data that was entered came from a mobile app created in Android Studio.
This is the code that I made when retrieving the User data.
function AddAllITemsToTable(User) {
id=0;
tbody.innerHTML="";
User.forEach(element => {
AddItemToTable(element.uid, element.fullName, element.organization, element.contactPerson, element.contactNo, element.location, element.emailAddress, element.status);
});
}
function GetAllDataRealtime() {
const dbRef = ref(database, 'Users');
onValue(dbRef,(snapshot) => {
var Users = [];
snapshot.forEach(childSnapshot => {
Users.push(childSnapshot.val());
});
AddAllITemsToTable(Users);
})
}
window.onload = GetAllDataRealtime;
Since you're calling onValue on /Users, you already get all data for all users and all of their donations. To process the donations in your code:
const dbRef = ref(database, 'Users');
onValue(dbRef,(snapshot) => {
var Users = [];
snapshot.forEach(userSnapshot => {
Users.push(userSnapshot.val());
userSnapshot.child("donation").forEach((donationSnapshot) => {
console.log(donationSnapshot.key, donationSnapshot.val());
});
});
AddAllITemsToTable(Users);
})
As I said in my comment, I recommend reading the Firebase documentation on structuring data, as the way you nest donations under each user does not follow the guidance on nesting data and keeping your structure flat.

get values from firestore query

I have this function:
firestore.collection('customers').doc(userID).collection('subscriptions')
.where('status', 'in', ['trialing', 'active']).get()
.then(activeSubscriptions => {
// if this is true, the user has no active subscription.
if (activeSubscriptions.empty === true) {
console.log("line 31")
{signOut(props.history)}
subStatus = "inactive"
}
});
Basically, in firestore, I have a customers collection, a doc with the user id, and then the subscriptions collection in which is created upon a user processing stripe. In the subscriptions collection, it has a doc which is the subscription id, and I have some fields I want to grab. See the attached picture:
I want to grab the current_period_end data so I can put it out on screen. how would I do this?
If you are looking to access fields from a firestore document, you can do it by specifying the field in square brackets.
With a firestore structure like /customer/cus123/subscriptions/sub123 I was able to obtain a timestamp field of sub123 with this code:
let cusRef = db.collection('customer').doc('cus123').collection('subscriptions').doc('sub123');
cusRef.get()
.then(doc => {
if (!doc.exists) {
console.log('No such document!');
}
else
{
console.log('Name: ',doc.data()['name']);
console.log('Tmsp: ',doc.data()['tmsp123']);
}
});
I hope you find this useful.

How to pass data of an object to HTML file

I have few posts in my app, and I want that when user selects one of them, he to be redirected to a Post.html page which contains all details about that specific product. I have two methods, createPost() for creating a product dynamically where I pass postId in order to keep track of that product, and getPosts() to get the posts from database. I am saving all posts in an array in localStorage to have data about the selected product in Post.html. I added an addEventListener() but not sure how to use it. The problem is that I am stuck how to get the information of that post and pass it to Post.html.
function getPosts() {
firebase
.firestore()
.collection("products")
.get().then(snapshot => {
let products = [];
snapshot.docs.forEach((doc) => {
products.push(doc.data());
createPost(
doc.data().title,
doc.data().description,
doc.data().price,
doc.data().postId
);
});
localStorage.setItem(`${products}`, JSON.stringify(products));
})
.catch((err) => {
console.log(err);
});
}
function createPost(title, description, price, postId) {
let div = document.createElement("div");
div.setAttribute("class", "product-home-show");
......
div.appendChild(divSellerRoundImage);
div.appendChild(divSellerName);
div.appendChild(divProductDescription);
div.appendChild(divProductName);
div.appendChild(divProductPrice);
productsCollection.appendChild(div);
div.addEventListener("click", function () {
// console.log(localStorage.getItem());
// window.location.href = "post.html";
});
}
You can get data from localStorage on another page. Use localStorage.getItem(keyName); Also keep in mind the first argument to setItem is the key name. I'd recommend changing your code to: localStorage.setItem("products", JSON.stringify(products));. Then you'll be able to retrieve your product list with they key "products."
Also, if you're saving an object, you'll need to parse it since it will be saved as a string. You can use JSON.parse
For example:
var retrievedData = localStorage.getItem("products");
var productListObject = JSON.parse(retrievedData);
You can save the selected post ID in another value in local storage, or a cookie. Lastly, you may want to consider using sessionStorage if you don't need the data stored after the session is over. See this link for more information

How to iterate a firebase database using javascript?

I need to iterate the users of my Firebase Database. I have a token for each user, and I want to send a notification to each user of the database.
My database looks like this:
console.log('Sending a notification to all users');
var ref = functions.database.ref('/users');
for (var token in ref){
console.log('Hello from: '+ ref.token);
}
Your ref is just a reference to a specific path in Firebase Realtime Database. You haven't queried it, so you don't have anything back yet. Try this:
console.log('Sending a notification to all users');
var ref = functions.database.ref('/users');
// Query the database
ref.once('value').then((usersSnapshot) => {
// Get back all the user records and iterate through them.
usersSnapshot.forEach((userRecordSnapshot) => {
// I'm guessing your record id is the token?
const token = userRecordSnapshot.key
// To get the other values, for example
const email = userRecordSnapshot.val().email
});
});```

Size of child in firebase

I am using react with firebase realtime database
So i have this firebase data and i want to count total values in followers. However, what i know is that firebase do not have such a function to count and you need to manually do it.
From below i can see all the user data such as username and email. However, i still cannot figure out how to count the number of followers.
I hope someone can help. Thank you.
const ref = firebaseDB.ref();
ref
.child("Users")
.orderByChild("email")
.equalTo(this.state.currentUserEmail)
.once("value", snapshot => {
let userData = {};
for (var childSnapshot in snapshot.val()) {
userData.key = childSnapshot;
// then loop through the keys inside the child object and get the values like price (key) : 44.95 (value)
for (var value in snapshot.val()[childSnapshot]) {
console.log(value);
console.log(snapshot.val()[childSnapshot][value]);
userData[value] = snapshot.val()[childSnapshot][value];
}
}
console.log(userData);
});
Something like this should do the trick:
const ref = firebaseDB.ref();
ref
.child("Users")
.orderByChild("email")
.equalTo(this.state.currentUserEmail)
.once("value", snapshot => {
snapshot.forEach((childSnapshot) => {
console.log(childSnapshot.child("followers").numChildren());
}
console.log(userData);
});
The changes/additions:
Use DataSnapshot.forEach() for a cleaner way to loop over the children.
Use DataSnapshot.child() to get the snapshot for the followers node.
Use DataSnapshot.numChildren() to determine the number of followers.

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