Develop Reference

Is there a plugin that will let me communicate with a PocketBase database?

I'm trying to connect with a running PocketBase database. Normally, I would use their Javascript SDK to achieve this, but the package does not get shipped to the mobile device during the build process.
This means I either have to build my own set of functions to mimic the working of the PocketBase Javascript SDK, or use a NativeScript plugin.
I could not find an existing plugin mentioning PocketBase, does anyone know of a plugin that facilitates this?
I tried to install the PocketBase Javascript SDK directly from NPM using npm install pocketbase, but this module does not check shipped to the mobile device during the build process.
For example:
import PocketBase from 'pocketbase'
console.dir(PocketBase)
Running this from a NativeScript app logs "null" to the console.

Using import * as PocketBase from 'pocketbase' ended up working for me.
I installed the pocketbase SDK with npm i --save pocketbase.
For whatever reason using import PocketBase from 'pocketbase' as the PocketBase documentation suggests doesn't work in this case.

Create an electron JS desktop app with python and react js

I want to create a desktop app with Electron JS and form front end I can use React JS as I'm familiar with it.
I have a good grasp of Python I checked over the internet but they all wanted me to create an API and run it on local I can do that and connect to react electron app but for distribution, I need the user to install Python as well.
I know I can go for node js as a backend but I have a lot of work ready in Python like backend logic and the app will run on desktop only no need to connect to Internet for that.
I need to know if I need user to install python as well. I don't want that.

I think this is exactly what you're looking for, it's a reusable Electron template that uses a React front-end with Redux & Redux Toolkit, and is integrated with Python/Flask for microservices. Packaging functions with build scripts are available for Windows and macOS.
You can just copy the parts you need or clone the template and use it.
https://github.com/iPzard/electron-react-python-template

If you don't want the user to have to install Python then you need to use something to package it together. Check out Pyinstaller, once you've created an exe it can be distributed and doesn't require the user to install Python
https://www.pyinstaller.org/

What is the role of Node.js in React-Native?

I'm trying to understand the development process of React-Native, so I've found information about Metro, And then I've read/watch this Metro video):
Metro is the development platform for React Native and it does that by
exposing an HTTP server so clients, in this case, emulators can
communicate with it and it also exposes a Websocket server so it can
push updates into the clients.
The docs talk about the "React Native Packager" (now called Metro, according to the video) which runs on port 8081, so that is the HTTP server that starts when we type react-native run-android for example?
Regarding the Websocket I still need to read more.
The documentation says we're running our JavaScript code in two environments, depending if we're in debug mode or not, which I understood. But this article confused me a little bit, says:
No. 4 You Code Does Not Run on Node.JS: The JavaScript runtime you’ve got is ether JavaScriptCore (non-debug) or V8 (debug). Even
though you can use NPM and a node server is running on the background,
your code does not actually run on Node.JS. So you won’t be able to
use of the Node.JS packages. A typical example is jsonwebtoken, which
uses NodeJS’s crypto module.
And, then I've read things like:
React Native uses Node.js, a JavaScript runtime, to build your
JavaScript code.
Node.js is a server-side JavaScript runtime environment. React
Native ships with some tools that are written for Node.js.
Node.js is an open source platform built on Chrome's JavaScript
runtime; it offers a way to easily build fast, scalable
programs. Node.js allows you to run JavaScript in Terminal, and helps
create modules.
In this article, it says:
Download node.js from nodejs.org. This JavaScript runtime gives you
access to npm, which is a convenient tool created by the node.js
project that you can use to manage open source packages. Make sure
that you download the latest LTS (Long Term Support) version of
node.js. Also included with this download is a development server
called the Metro bundler, which provides live updates when debugging.
So:
The role of Node.js in RN is to only access npm and manage the packages? and is Metro is includes in Node.js? Am I missing/confusing something? Thank you.

There are four types of JavaScript you'll write in todays environments:
1) Clientside browser JavaScript:
That's what gets sent to webbrowsers when they visit your webpage, it then gets executed in the browser at the clientside. As you want the JS to load fast and run on all kinds of browsers, you usually use transpilers to turn the modern ESnext you write into a minified version with better support.
2) Clientside native JavaScript:
Most devices do have a native JS runtime, therefore you can ship JS files with your Android / iOS / Desktop application and then start them there. These engines also support adding hooks from JavaScript into your native code, that's how React Native does provide it's APIs.
3) Serverside NodeJS JavaScript:
NodeJS is a runtime you'll use to run servers.
4) Buildscripts running on NodeJS:
You can use JavaScript to generate JavaScript files. That's how you bundle the files for (1) and (2) (maybe also (3)).
Now metro is a serverside buildscript (on NodeJS) that you can use to either a) start a server that serves your JS as a webpage (1 & 3), or b) that bundles your JS in a native App that you can install on your device (2).
The role of Node.js in RN is to only access npm and manage the packages?
No. metro is itself a package that you then run on NodeJS.

Module not found: Error: Can't resolve 'dns' when using MongoDB

I'm new to Reactjs, Nodejs and MongoDB. I'm currently trying to change Mediums snowflake tool to store users scores in a database. I have installed yarn, mongodb and mongodb-core through npm. It is a single page web application which is what I think is causing me trouble. I add
var MongoClient = require('mongodb');
To SnowflakeApp.js and encounter the following error:
Module not found: Error: Can't resolve 'dns' in
'/home/mlAHO174/snowflake/node_modules/mongodb-core/lib'
I've tried googling this error and have discovered it could be a range of things. I'm not sure if it is because React is front end and I'm trying to alter back end or because mongoDB is installed incorrectly. I'm new to this so would be grateful for help!

DNS is a core module of Node.JS. Telling people they need to install DNS via NPM will end up with them having a completely different module that does something else.
https://nodejs.org/api/dns.html vs https://www.npmjs.com/package/dns
This error most likely means you are trying to do something from the client-side that needs to be done on the server-side. If MongoDB module can't find the DNS component, it's running on the client-side.
MongoDB has to run on the server. In order to access data from React dynamically you'll need to set up an API using something like Express or Apollo.
Update:
A great way to do this is with Azure Functions (TypeScript) or AWS (Lambda) functions

For anyone who encounters this Error while importing the clientPromise (like in the with-mongodb template):
Make sure you're in the /pages/ directory!
It won't work in other directories like /components.
(and you should take a break or get some coffee...)

The problem is that you are trying to connect to the database from the front end. If this were possible that would open up a whole world of security issues. You need to set up your database connections on the backend and then have the front end make requests to the backend to handle the database.

I solved this by installing and using 'bson' instead of 'mongodb' for the client part of the code. 'bson' has a tiny bit of what 'mongodb' has and it might have what you are looking for. 'bson' is built for the browser.
In my case I needed the "ObjectId" in the browser and pulling it in from 'bson' did the trick as I didn't want to reference 'mongodb' because of the error described in the OP.
The other answers are also correct depending on why you're getting this error.

I think - mongo package is meant to be run on servers only, not in the browser.
It does not work in Next.js pages file components too, but does work in getStaticProps, getServerSideProps, getStaticPaths etc - because they run on the server, not the client.
Alternative - use Firebase Realtime database, you can access it in client-side code too. Example - a website (say a React app) that is hosted on GitHub pages or some other static server, but doesn't have a web app server (aka backend).

welcome to stack overflow.
You need to understand and learn few basics of web-applications. There's frontend, backend and a layer between them and a layer between backend and database. Frontend includes react.js, angular.js or anything else that is on browser. Backend is used to take request from frontend, providing API's to frontend and ask for data from other API's or database. Database includes sql, no-sql.
The error you are facing if of a NPM module mongodb-core.js. Either it's not installed properly, or installed using wrong version of module which is not comparable with your node version, or wrong version of NPM, or module using another NPM module which is not installed.
The issue in your case is mongodb-core uses a module dns which is not been installed. Try to install dns with npm i dns. or remove and install mongodb-core again.

How to find whether software is installed or not in windows/mac using javascript or nodejs

My requirement is using Javascript I need to check whether xyz.msi/xyz.pkg application is installed or not in windows & mac system.
But I could not find any solution so I am trying through NodeJS. I have the following doubts
Will NodeJS help me to achieve above requirement?
Is there any way to get list of installed application using nodeJS
or by passing particular application name can I get information about that application using NodeJS.
If anyone has ideas, Please kindly share it.

tips：
I'm not sure javascript but node.js.
when you exec your project in node.js, you've has operate permission to do anything on your platform of os.
you can use child_process of node.js to exec shell on your pro and watch stdout to check if you have installed.