No matter what I do I can't seem to figure out a way to access the child "onSite", which shows as being there when I log snapshot.val(), but I cannot figure out how to access it.
Code:
firebase.database().ref().child("users").orderByChild('facebook_id').equalTo(fbID).once("value").then(function(snapshot) {
console.log(snapshot.val());
console.log(snapshot.child("onSite").val());
});
Here is the response:
It shouldn't be null, it should be false. I can't do child("4mUUjF...").child("onSite").val() because I don't know what the ID is before the query. Using an each loop doesn't work, it only loops through the first level, which is the ID.
Use the key of the object
Get the snapshot val and then find the key with the Object.keys method. This will allow you to then get inside the snap. Once there it's a simple matter of accessing the values like any other object.
firebase.database().ref().child("users").orderByChild('facebook_id').equalTo(fbID).once("value").then(function(snapshot) {
let snap = snapshot.val();
let key = Object.keys(snap)[0]
console.log(snap[key].onSite);
})
When you execute a query against the Firebase Database, there will potentially be multiple results. So the snapshot contains a list of those results. Even if there is only a single result, the snapshot will contain a list of one result.
Your code needs to handle the list, by using Snapshot.forEach():
firebase.database().ref().child("users").orderByChild('facebook_id').equalTo(fbID)
.once("value").then(function(result) {
result.forEach(function(snapshot) {
console.log(snapshot.val());
console.log(snapshot.child("onSite").val());
});
});
Related
I'm trying to access data from a firestore document, but I'm getting an error message that exercise.data() is not a function. I don't understand how the exercisesToAdd array is an array of documents, but I can't use .data() to get the contents of the items? How else would I go about getting the data from those documents?
I know the exercisesToAdd array is actually being filled with documents because I see them in the database when I send the array. Seems straight-forward but I must be missing something.
chosenExercises.forEach((exercise) => {
exercisesToAdd.push(doc(db, 'Users/' + auth.currentUser.uid + '/Exercises/' + exercise));
});
exercisesToAdd.forEach((exercise) => {
console.log(exercise.data());
});
As #Doug Stevenson stated in his comment:
Your code hasn't actually performed any queries, so there is no document data available. Please review the documentation and use get() to execute each document query first before calling data() on anything. All doc() does is create a DocumentReference, which doesn't contain any data.
I want to read last message node as shown in image below.
I am using below query to retrieve last message where suid and ids are known(as shown in img). but not working.
firebase.database().ref("Messages/"+suid).child(ids+"/chat").orderByKey().limitToLast(1);
How to retrieve last message from firebase realtime db and display it to my console? Thanks
Your existing code looks fine, so let's store that query in a variable first:
const query = firebase.database().ref("Messages/"+suid).child(ids+"/chat").orderByKey().limitToLast(1);
Now you can read the message(s) this query matches with either once() or get(). I'll use once(), since it's much older and hence you're more likely to find examples of it elsewhere:
query.once("value").then((snapshot) => {
snapshot.forEach((message) => {
console.log(message.val().message.msg);
});
})
Some things to note here:
Since a query may have multiple results, the snapshot contains a list of those results. Even if there's only a single result (like here), the snapshot is a list of one result. To loop over these results, we use snapshot.forEach().
Your msg is nested under message in each child, so we use message.val().message.msg to get at its value.
I'm trying to get firebase data from a node which uid must start with a passed string.
I tried a code but I always get the same data. The database data is as following:
And I'm using the following code:
var ref = firebase.database().ref("restaurantes/history");
ref.orderByKey().startAt(userUID).once("child_added", function(snapshot) {
snapshot.forEach(child => {
if(child.key == "orders")
{
console.log(child.val());
_.each(child.val(), (value, key) => {
arrtmp.push(value)
})
}
})
If user is "FKQLlqa" I should get the history data shown in the picture. If I user is "abc" I shouldn't get any data. But I always get the data shown in the picture. Should I use another way of querying? Or I should use a key field inside orders and payments data?
Regards!
Try the following:
var ref = firebase.database().ref("restaurantes/history");
ref.child(userUID).once("value", function(snapshot) {
if (snapshot.exists()) {
console.log(snapshot.val());
}
else {
console.log("different user");
});
This will check if the snapshot that contains the userId (added as a parameter in the child() method), already exists in the database then you will be able to retrieve the data under the userId.
For reference:
https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#exists
Peter's answer is the correct solution. I'm merely adding this for completeness.
When you call orderBy... on a Firebase reference, the database orders all child nodes on the key/value/child that you specify.
If you then subsequently call startAt(...) on the query, it finds the (first) node that starts with that value and starts returning all results from there. So if you start at FKQLlqa, it will start returning keys at FKQLlqa and then return all keys after it.
If you want to return the child node(s) with a specific key/value/child, you'd use equalTo(...). So:
ref.orderByKey().equalTo(userUID).once("child_added", function(snapshot) {
...
But as Peter said already, this is just a more expensive way to look up a child with a known key. I highly recommend using his better approach: ref.child(userUID).once("value".
I have following structure of firebase database:
-files
|-LJsSTIfXcyzZy9N8RDV
|-fileURL:"uploads/myfile.png"
|-LJsSTIfXcyzxy9N8PqT
|-fileURL:"uploads/myfile2.png"
Now i want to add a sibling of fileURL by using only value of fileURL.
So using value 'uploads/myfile.png' i am trying to acheieve following:
-files
|-LJsSTIfXcyzZy9N8RDV
|-fileURL:"uploads/myfile.png"
|-fileThumbURL:"uploads/myfileThumb.png"
|-LJsSTIfXcyzxy9N8PqT
|-fileURL:"uploads/myfile2.png"
I have tried following but it doesn't work.
fileURL = "uploads/myfile.png";
thumbURL = "uploads/myfileThumb.png";
admin.database().ref().child('files').orderByChild("fileURL").equalTo(fileURL ).once('value',function(snapshot){
return snapshot.ref.child('fileThumbURL').set(thumbURL);
});
When you execute a query against the Firebase Database, there will potentially be multiple results. So the snapshot contains a list of those results. Even if there is only a single result, the snapshot will contain a list of one result.
Your code needs to handle this list, typically by using snapshot.forEach() to loop over the results. For example:
admin.database().ref().child('files').orderByChild("fileURL").equalTo(fileURL ).once('value',function(snapshot){
snapshot.forEach(function(fileSnapshot) {
fileSnapshot.child('fileThumbURL').set(thumbURL);
});
});
This is my first app project using Google Cloud Functions & Firebase. I'm trying to find away to get a single value of the array that I'm returning and compare it to a set variable and if it matches, update another child's value in that same account.
My App users can add records to the database under their login/user_id that is stored in the database. I'm trying to get a list of the "RecordName" that is a child under that login/user_id that every user has stored in their account.
So basically every "RecordName" in the entire database. When I want to run specials for those records, I need to match the name of that record to the name of the record I have on special and if there is a match, update another child value under that user's account ("special" = true.). This way, when they load their app next time, I have it highlighting that record so they know it's on special.
When I use..
const ref = admin.database().ref(`/store`);
...with the following code...
ref.on('value', function(snapshot) {
// puts ALL items of the object into array using function ..
console.log(snapshotToArray(snapshot));
});
... and the function...
function snapshotToArray(snapshot) {
var returnArr = [];
snapshot.forEach(function(childSnapshot) {
var item = childSnapshot.val();
item.key = childSnapshot.key;
returnArr.push(item);
});
return returnArr;
};
... I get the entire array just as it is in the database:
-store
-{ones_users_id}
-recordname: value1
-special: false
-{anothers_users_id}
-recordname: value2
-special: false
ect. ect.
If my record on special is called, "Newbie Record", what would be the best way to take out every individual value for the key: "recordname" from the array, compare each one to var = "Newbie Record" and if they match, update the value of the key: "special" to be true?
I'm new to JSON and NodeJS, I've been searching on here for answers and can't find exactly what I'm looking for. Your feedback would be very helpful.
It sounds like you're looking to query your database for nodes that have "recordname": "Newbie Record" and update them.
An easy way to do this:
const ref = admin.database().ref(`/store`);
const query = ref.orderByChild("recordname").equalTo("Newbie Record");
query.once('value', function(snapshot) {
snapshot.forEach(function(child) {
child.ref.update({ special: true })
});
});
Main differences with your code:
We now use a query to read just the nodes that we want to modify.
We now use once() to read the data only once.
We loop over the children of the snapshot, since a query may result in multiple nodes.
We use the reference of each child and then update its special property.
I recommend reading a bit more about Firebase queries in the documentation.