How can I fix my firestore database setup error? - javascript

i'm trying to setup this event booking webapp from a source code that I downloaded. When i first set it up it throws me this error:
db.js:3 Uncaught TypeError: Cannot read properties of undefined (reading 'doc')
at Object.next (db.js:3:47)
at next (database.ts:1973:20)
at async_observer.ts:51:11
I searched the error to find a solution for this issue, but I couldn't find any. I'd greatly appreciate it if someone could help me with this issue. I have provided my code below. Thanks!
db.collection("events").onSnapshot((snapshot) => {
// Handle the latest event
const newestEvent = snapshot.docChanges()[0].doc.data();
const id = snapshot.docChanges()[0].doc.id;
showLatestEvent(newestEvent, id);
// shift the latest event element
snapshot.docChanges().shift();
snapshot.docChanges().forEach((event) => {
showEvents(event.doc.data(), event.doc.id);
});
});

Most likely snapshot.docChanges() is an empty array, so snapshot.docChanges()[0].doc.data() then fails. You'll want to check for an empty result set before accessing a member by its index like that.

Related

discord.js Stop that the Bot is turing off after an Error

Hey everytime i get an Error the Bot turns off... And i dont want that. Can i somewhere turn it off or something like this?
I tried something like
client.on("error", () => { client.login(config.token) })
But thats not working. Some of the Errors are:
TypeError: Cannot read property 'id' of null
D:\Discord Bot\Space Network\spacenetwork\node_modules\discord.js\src\client\actions\ChannelCreate.js:9
const existing = client.channels.cache.has(data.id);
at ChannelCreateAction.handle (D:\Discord Bot\Space Network\spacenetwork\node_modules\discord.js\src\client\actions\ChannelCreate.js:9:53)
at User.createDM (D:\Discord Bot\Space Network\spacenetwork\node_modules\discord.js\src\structures\User.js:257:46)
at processTicksAndRejections (node:internal/process/task_queues:94:5)
at async D:\Discord Bot\Space Network\spacenetwork\index.js:663:22
TypeError: Cannot read property 'setActivity' of null
That is because your code has errors in it, the best practice is to fix the error instead of bypassing it TypeError: Cannot read property 'id' of null this means, whatever that comes before 'id' property is null
const existing = client.channels.cache.has(data.id); the error is at this line, try logging data.id, according to the error 'data' is null, fix that and it should solve the problem
The point to note is, reading the errors, finding the source of the error and fixing the error :)
You can use nodemon. I think they make it so that whenever you make changes to your code and save it, it automatically runs, and if it crashes, it restarts it automatically. However, I’d be careful with this, considering if have the error in the ready message, the bot will connect over and over again, and I think discord will automatically shut it down.
npm install nodemon -g

How to fix Uncaught TypeError: Cannot read property 'children' of null

carousel.js:5 Uncaught TypeError: Cannot read property 'children' of null**
I got this error when I'm going to ad slider to the page.
here is the js code for the error.
const track = document.querySelector('.carousel_track');
const slides = Array.from(track.children);
const dotsNav = document.querySelector('.carousel_nav');
const dots = Array.from(dotsNav.children); //here
const slideWidth = slides[0].getBoundingClientRect().width;
slides[0].style.left = 0;
slides[1].style.left = slideWidth + 'px';
Can anyone give me a solution for this? I really appreciate your help.
Apparently the error throws here const dots = Array.from(dotsNav.children); //here , though the source of error is coming from previous line.
The error hints that the track is null, which can happen when the selector didn't return any value.
Without seeing your HTML code its not so clear whats the exact reason, but its obvious that the element with class carousel_nav doesn't exist in the DOM at the moment of execution of this code.
Steps to debug:
Do the console log after acquiring the track object.
const dots = document.querySelector('.carousel_nav');
console.log('Dots are: ', dots);
...
Then on the console of the browser check the value, its probably null.
Check if the class is written correctly on the HTML element, without typos and mistakes. You can even run the js directly on the browsers console to see if the code is actually fetching .carousel_nav
If when you run your js code in browser's console and it returns actual value instead of null, but on the page load it still returns null then it can mean the carousel is being initialized by 3rd party library after certain event, most probably document.ready, you have to as well listen to the document ready event and only after that execute your code.
Sometimes just waiting for the document ready is not enough, so check the documentation of the library that you use, it should have some callback where you can execute your code exactly after the carousel is being initialized.
Might be that the carouself library that you use, need an additional parameter to render dots, do you actually see the dots in the rendered dom?
If you need more hints, provide the library name youre using and also html
P.S.
Sorry I didn't see //here comment. But the debugging steps are the same

React-Native Simple Store Error: Unable to load RocksDB, SQLite, or AsyncLocalStorage

When running a basic app that uses react-native-simple-store I get the following error (the same as this unsolved question):
undefined is not an object (evaluating 'RCTAsyncStorage.multimerge')
<unkown>
AsyncStorage.js:325:21
...
Digging into AsyncStorage.js I find that the issue is here:
// Not all native implementations support merge.
if (!RCTAsyncStorage.multiMerge) {
delete AsyncStorage.mergeItem;
delete AsyncStorage.multiMerge;
}
RCTAsyncStorage is not undefined. The attempt to define RCTAsyncStorage comes at the beginning of the same file.
const NativeModules = require('../BatchedBridge/NativeModules');
// Use RocksDB if available, then SQLite, then file storage.
const RCTAsyncStorage = NativeModules.AsyncRocksDBStorage ||
NativeModules.AsyncSQLiteDBStorage ||
NativeModules.AsyncLocalStorage;
Finally, I checked NativeModules.AsyncRocksDBStorage, NativeModules.AsyncSQLiteDBStorage, and NativeModules.AsyncLocalStorage—surely enough, all of them were undefined. The file from which they are supposed to be loaded (NativeModules) is a bit difficult to understand, so I stopped tracing there.
Please let me know if you know what I could be doing wrong!

Uncaught TypeError: Cannot read property 'find' of null.jquery

Getting the error "Uncaught TypeError: Cannot read property 'find' of null." in the console. Underlining this line of code containing the error:
if ($sResults.find("product").length > 0)
Anyone have any idea why this is happening. Im a beginner so any adivce would help. Thanks.
if ($sResults.find("product").length > 0) {
// We have some search results
// The products are in $sResults
} else {
// We don't have any results
// Hide the table
$("#mainBody").find("table").hide();
$("#mainBody").append("<h3>There are no search results. </h3>");
}
$sResults is null, for whatever reason. Perhaps you are hitting an API or otherwise dynamically getting that info and nothing is being returned, or perhaps you have that info available locally and it is not being passed correctly - either way, you are calling .find on null and that is the issue. It may be okay, if fetching the info dynamically, to have no results, right? If it's not - that is one of two problems because your first (and current
) problem is that your code is breaking. It's breaking because you are not protecting it by checking to see if $sResults HAS a value before you run .find()
For a more precise answer on WHY you are getting a null value, we would need more code ;)
Try this:
if ($sResults && $sResults.find("product").length > 0) {
// We have some search results
// The products are in $sResults
} else {
// We don't have any results
// Hide the table
$("#mainBody").find("table").hide();
$("#mainBody").append("<h3>There are no search results. </h3>");
}

What can cause 'TypeError: undefined is not an object...`

From my bugtracker I am seeing this error when deployed:
TypeError: undefined is not an object (evaluating 'e.getRegion("similarRegion").show')
I am trying to reproduce and resolve this but having some trouble diagnosing it. Here is the code where the error is caused:
similarProductView() {
var view = new SimilarProductView({
collection: this.model.get('relatedProducts'),
initialLoading: true
});
this.model.getRelatedProducts().always(() => {
this.getRegion('similarRegion').show(view);
});
},
My main question is what can raise this error? What I have tried, that results in different errors, are making the region a different name (causing the region to not exist), and trying to show a variable that doesn't exist.
Any ideas on what situation would raise this error? Or any suggestions on things to try to reproduce it?

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