Why is my snapshot returning null, even though there are values in the Firebase Database?

I am currently facing an issue in my code related to the snapshot. Specifically, I am trying to retrieve the value of quantity from my Firebase Database. Here's a snapshot of my database:

https://i.sstatic.net/qN6m4.jpg

and

https://i.sstatic.net/Gw0dv.jpg

 firebase.database().ref("mycart/"+uid+"/"+imguid).once("value").then(function(snapshot) {
        console.log("uid="+uid); 
        console.log("imguid="+imguid); 
        console.log("snapshot.val()="+snapshot.val()); 
        if(snapshot.exists()){
           console.log("snapshot"+snapshot.key); 
        }
        console.log("snapshot doest exists"); 
    });
javascriptfirebasefirebase-realtime-database

Answer №1

Consider giving this a shot:

firebase.auth().onAuthStateChanged(function(user) { 
 if (user) { 
 uid = user.uid;
 firebase.database().ref("mycart").child(uid).child(imguid).once("value").then(function(snapshot) { 
   if(snapshot.exists()){ 
       console.log("snapshot"+snapshot.key);
      } 
      console.log("snapshot does not exist"); 
    }); 
   }
  else{ } });

The uid was returning null, resulting in that error. The process of retrieving authentication data in Firebase is asynchronous, so if you need to use the uid to retrieve data from the database, it should be done within the onAuthStateChanged function.

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Escaping the setTimeout loop

I'm struggling to find a solution for breaking out of a setTimeout loop. for (var i = 0; i < 75; i++) { setTimeout(function (i) { return function () { console.log("turn no. " + i); if (table.game.playerWon) { con ...

javascriptnode.js

React component making an Axios request only receives the initial state as a response

I'm struggling with creating an AJAX call using Axios in React. Despite my efforts, I can't seem to pinpoint where the issue lies. Below is what I currently have within my component: ComponentDidMount() { axios.get('https://jsonplacehol ...

javascriptarraysajaxreactjsaxios

Identifying when an element hovers over a particular section

I am facing an issue with the side dot navigation on my website. The navigation is standard with a fixed position, but I also have two types of sections with different backgrounds - one white and the other black. The problem arises when the dots are not vi ...

javascriptjquery

JavaScript Code for Executing Function on Checkbox Checked/Unchecked

My goal is to display an image when the checkbox is checked and show text when it is unchecked. However, I am facing an issue where the text does not appear when I uncheck the checkbox. <input type="checkbox" id="checkword" onchang ...

javascripthtml

Allow the json array to be transformed into a format suitable for input

Hey there, I've received a JSON array as the response of my ajax request: {"chart":{"2016-03-08":"1","2016-03-07":"4","2016-03-06":0,"2016-03-05" :0,"2016-03-04":0,"2016-03-03":"145","2016-03-02":0}} Now, I'm looking to create a chart using the ...

javascriptjqueryarraysjsoncharts

"Refine Your Grid with a Pinterest-Inspired

I've set up a grid of images in columns similar to Pinterest that I would like to filter. The images vary in height but all have the same width. The issue arises when a taller image is followed by a shorter one, causing the short image to float right ...

javascriptjqueryhtmlcss

What techniques can I employ in Angular to develop engaging widgets using plain HTML, without any Angular-specific elements?

I am currently developing a cutting-edge Angular application that serves as a training platform to offer online courses to users. Each course is essentially a set of "slides," which are HTML partials through which the user can navigate in order. These sli ...

javascriptangularjs

Problem with Custom MUI fields not detecting value change

I want to make custom form components so I don't have to update each item individually if I want to change the style. The ReportSelect component doesn't update the value when a menu item is selected, and the ReportTextField only works for the fir ...

javascriptreactjsmaterial-uijsxreact-props

Display information in real-time based on user input using Highcharts

I am trying to display data using highcharts on my index.php page. Can anyone help me with this?, here is what I have attempted so far: This is the HTML code I have: <!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" cont ...

javascriptphphighcharts

Changes made to one order's information can impact the information of another order

Currently, I am in the process of developing a unique shopping cart feature where users input a number and a corresponding product is added to a display list. Users have the ability to adjust both the price and quantity of the products, with the total pric ...

javascriptangulartypescript

Is there a way to track the number of visits by a 'user' to a website?

Looking to hide certain parts of my website from users who have visited more than a specified number of times. The NY Times site has something similar. Utilizing react & firebase for this project. Considered using IP addresses, but it seems to identify l ...

javascripthtml

Django not receiving data from AJAX GET request

I am attempting to transmit data stored in localStorage through an AJAX GET request to Django, but the Django server does not seem to receive it. I have verified that there is data in localStorage("preselection") as indicated by the output of console.log. ...

javascriptpythondjangoajax

What sets apart custom events from postMessage?

If you want to send a message to another document, such as an iframe, there are two functions you can use - postMessage and createEvent. Consider the following: var event = document.createEvent('CustomEvent'); event.initCustomEvent("message", tr ...

javascripthtmlpostmessagecustom-events

What is the best way to modify the text color within a Navbar, especially when the Navbar is displayed within a separate component?

First question on StackOverflow. I have a Next App and the Navbar is being imported in the _app.js file. import Navbar from "../Components/Navbar"; function MyApp({ Component, pageProps }) { return ( <> <Navbar /> ...

javascripthtmlcssreactjsnext.js

What could be the reason for the "begin" script failing to execute?

I have a simple node and express application that works as expected, but I encounter an issue when trying to run the server from the script. When my script is set to "start", running the command simply opens my cmd. However, if my script is set to any oth ...

javascriptnode.jsexpressnpm

Is it not recommended to trigger the 'focusout' event before the anchor element triggers the 'click' event?

In a unique scenario, I've encountered an issue where an anchor triggers the 'click' event before the input field, causing it to lose focus and fire the 'focusout' event. Specifically, when writing something in the input field and ...

javascripthtml

Node-archiver: A tool for dynamically compressing PDF files

I am currently working on a project that involves generating multiple PDF files using pdfkit. I have an array of users, and for each user, I create a report using the createTable() function. The function returns a Buffer, which is then passed to archiver t ...

javascriptnode.jsnode-archiver

Randomly undefined custom jQuery function

Appreciate your assistance in advance. I am facing a peculiar scope issue on a page where multiple charts are rendered intermittently. I have created a set of jQuery functions to display different types of charts based on the provided options. Each funct ...

javascriptjqueryajax

Using the jQuery.grep() method to sort through data

I have been attempting to filter data that is stored in a .js file using the jQuery.grep() method, but unfortunately, the data is not loading as expected. Data var myData = { "type": "FeatureCollection", "crs": { "type": "name", "properties": {"name": ur ...

javascriptjquery

When attempting to access the Object data, it is returning as undefined, yet the keys are being

I have an Object with values in the following format: [ { NameSpace: 'furuuqu', LocalName: 'uuurur', ExtensionValues: 0, FreeText: 'OEN', '$$hashKey': 'object:291' }, { Nam ...

javascriptjsonobjectstringifyjsonparser