Usage of npm scala-node - node.js

I want to use scala object in node js as one of the modules. After some investigation, I found this npm plugin called scala-node (not sure if this will work).
But I don't know how to use it. It would be helpful if I get few examples if someone has used it to understand the functioning of this plugin.

How much do you want this library?
scala-node is for node interop with scala.js, which is another "compile to js" project, this time using scala. If you manage to compile this scala library with scala.js (may be a headache, depending on its dependencies). You might then need scala-node to modularize the compile scala.js? Not sure.
Probably be easier to have an application in scala that your node.js application communicates with. What library are you wanting to take advantage of?

Related

Why we have to install NodeJS for ReactJS

I'm a beginner in ReactJS also for NodeJS. I would love to know why we have to install NodeJS run ReactJS application as ReactJS is client-side scripting.
The other answer is incorrect.
You don't NEED Node.js, in fact you could create a project without running a single npm command. Just follow this guide.
The main reason, as pointed out in the article, is:
Easy package management. This means you can upgrade the package easily later on
JSX is the templating language that makes it way easier to write components: <h1>Hello Word</h1> reads so much better than React.createElement('h1', null, 'Hello World')
Managing module imports, as opposed to having global variables around everywhere, it's great to have encapsulation and import modules as needed.
Build step and workflow. For a modern project, you will need tools to minify your code, cache busting, transpiling (writing pure javascript for old browser is a pain and you really shouldn't do it manually), the list goes on and on.
Because almost all the JavaScript libraries/frameworks are using the Node Package Manager (NPM), that makes much more convenient to manage JavaScript dependencies in general, both client-side and server-side.
Edit: It's not really technically necessary, but using a package manager is the best practice for managing dependencies and sub-dependencies.
Of course, you don't have to. When you are in the development step, you can install it for package management. Only webpack is needed to bundle, compile, transpile the code.

node js - How do I create build for commercial usage?

I am working on node js application and it is now ready to use. I want to make exe of this application so that it can be used for commercial usage.
Up to now I have used enclose module using which I have compiled the code of application but I have found some issues in that (app got crash on idle condition). App is running good without enclose or compiled code.
I have searched on google and found some alternate modules like JXcore, Node webkit and Electron etc. but JX core giving error same as in SO question.
In node web-kit, it's functionality is not looking suitable as we need its executable and some dll's along with our code, which makes our package bulky.
I have also tried jxcore. The main problem with the exe's and with modules that we use is their ability to work with native modules, in my case the Kinect.node module. This module cannot be compiled. We need a workaround to package only this along with our .exe file. Enclose provides this workaround in its inbuilt functionality.
Also looking a response from EncloseJS, which is actually run by just one person who gives further instructions upon purchase. A purchase is needed for commercial usage.
In case of Electron, It is supporting only Electron-based application source code. So If I choose this then I have to modify my application code.
So can any one suggest me what can I do to make exe file from node js code there?
Thank you!
I had the same issue before, the node js application close when running in background. now i am using process manager2 (pm2), it is working fine and if the application is crash due to any other reason it is automatically started again.
I have gotten my answer:
First, reason was DiskDB database, it was not compatible with the node webkit so that is why I was getting error of native modules.
Now I am using sqlite3 module for local database. It is better than DiskDB.
Second, One reason was free version of enclose, Paid version of Enclose JS module ignores the timeout issue which I was getting.
This way I have resolved my question.

How to use typescript/flow in nodejs without compiling it

Can someone give me some advice or links for discussion on whether I should bundle JS for backend?
I tried to Google with this title (and similar words) and I can't get any useful links.
Just want to know, say I am using latest Node.JS (es6-ready), should I bundle/compile the JS? If not, how am I suppose to use typescript/flow?
Thank you.
I feel like you are asking two different questions. I'll try to answer both.
How can I just run TypeScript code?
This is the one your question's title seems to ask ("How to use typescript/flow in nodejs without compiling it"). For this, you can use the ts-node package on npm. But it's usually not a good idea to use ts-node over just compiling when running in production because it tends not to be as fast.
How should TypeScript code get distributed to be run?
Any TypeScript code will need to get compiled from .ts files to .js files to eventually be run. Basically something like the same thing applies to Flow code.
If you plan to distribute a package written in TypeScript, you should be publishing the .js and .d.ts files together. This is so that
Your package consumers don't have to recompile your package. (they already get .js files.
Your non-TypeScript consumers don't need to install TypeScript to use your package. (they already have runnable .js files)
Your TypeScript consumers can get good type safety and completions. (they get your .d.ts files)
For more information, see the TypeScript documentation on Publishing Declaration Files.

What are the trade-offs of writing conventional node modules in ES6 with a babel workflow?

When developing front-end code for the browser, I often use the es2017 preset when transpiling down to a distribution bundle, which allows me all the conveniences of the included transformers. For conventional modules, I usually stick to whatever the required node engine I've specified for that particular module supports.
I would like to start developing these "conventional" modules using babel transformers as well, but I can foresee drawbacks to this, including:
It might inhibit the debugging workflow (more specifically when working with an IDE)
The performance of the module might suffer
What's the current state on this matter - would you say it makes sense to use babel in conventional modules given the aforementioned and other trade-offs? What are the pros/cons for your preferred workflow?
Bonus question: What are some reputable modules and/or module authors out there that are already using this technique? I've seen Facebook do it for their react ecosystem but I guess that makes sense since those are mostly modules for the browser.
It is converted back to vanilla JS (babel does that part).
What you get is that you can utilize Classes which I found useful.
Hopefully with time, browsers will support ES6 and we will not need babel.
The only drawback is that when debugging, you have to produce a source map, but that is temporary, see above.
To answer your second question: I'm using React in one of the websites, and most of the modules I needed (from npm) are using ES6.
I believe that the trade-offs or drawbacks that you mention both do not apply to developing nodejs code using babel as ES7 transpiler. Personally, I find using ES7 features with node tremendously productive.
There is source map support for debugging. I use karma for testing and it comes with excellent source map support (I use IntelliJ but I believe most IDEs will do). You can checkout this REST-API repository on github. It's a nice stack for building nodejs data backend. It uses karma for testing - even comes with code coverage support. It also integrates with pm2 for scaling and availability.
Regarding performance: I think transpiled code has been shown to run faster in many scenarios than the code a developer would write when not having advanced language features available. I will post some links later.

Is there a way to compile node.js source files? [duplicate]

This question already has answers here:
Is it possible to create desktop applications with node.js? [duplicate]
(5 answers)
Closed 7 years ago.
Is there a way to compile a node.js application?
I maybe very late but you can use "nexe" module that compile nodejs + your script in one executable: https://github.com/crcn/nexe
EDIT 2021: Nexe's latest release is from 2017 and it appears that development has otherwise slowed, so the more-widely-used alternative from Vercel should also be considered these days: pkg
Node.js runs on top of the V8 Javascript engine, which itself optimizes performance by compiling javascript code into native code... so no reason really for compiling then, is there?
https://developers.google.com/v8/design#mach_code
EncloseJS.
You get a fully functional binary without sources.
Native modules also supported. (must be placed in the same folder)
JavaScript code is transformed into native code at compile-time using V8 internal compiler. Hence, your sources are not required to execute the binary, and they are not packaged.
Perfectly optimized native code can be generated only at run-time based on the client's machine. Without that info EncloseJS can generate only "unoptimized" code. It runs about 2x slower than NodeJS.
Also, node.js runtime code is put inside the executable (along with your code) to support node API for your application at run-time.
Use cases:
Make a commercial version of your application without sources.
Make a demo/evaluation/trial version of your app without sources.
Make some kind of self-extracting archive or installer.
Make a closed source GUI application using node-thrust.
No need to install node and npm to deploy the compiled application.
No need to download hundreds of files via npm install to deploy your application. Deploy it as a single independent file.
Put your assets inside the executable to make it even more portable.
Test your app against new node version without installing it.
There was an answer here: Secure distribution of NodeJS applications. Raynos said: V8 allows you to pre-compile JavaScript.
You can use the Closure compiler to compile your javascript.
You can also use CoffeeScript to compile your coffeescript to javascript.
What do you want to achieve with compiling?
The task of compiling arbitrary non-blocking JavaScript down to say, C sounds very daunting.
There really isn't that much speed to be gained by compiling to C or ASM. If you want speed gain offload computation to a C program through a sub process.
Now this may include more than you need (and may not even work for command line applications in a non-graphical environment, I don't know), but there is nw.js.
It's Blink (i.e. Chromium/Webkit) + io.js (i.e. Node.js).
You can use node-webkit-builder to build native executable binaries for Linux, OS X and Windows.
If you want a GUI, that's a huge plus. You can build one with web technologies.
If you don't, specify "node-main" in the package.json (and probably "window": {"show": false} although maybe it works to just have a node-main and not a main)
I haven't tried to use it in exactly this way, just throwing it out there as a possibility. I can say it's certainly not an ideal solution for non-graphical Node.js applications.
javascript does not not have a compiler like for example Java/C(You can compare it more to languages like PHP for example). If you want to write compiled code you should read the section about addons and learn C. Although this is rather complex and I don't think you need to do this but instead just write javascript.

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