How to import a Deno library into a Node project? - node.js

I would like to create a TypeScript library in Deno.
If I do this, how can developers using Node use my library?

This is covered in section 8.1.1 of the Deno manual:
dnt - Publishing Deno modules for Node.js
Library authors may want to make their Deno modules available to Node.js users. This is possible by using the dnt build tool.
dnt allows you to develop your Deno module mostly as-is and use a single Deno script to build, type check, and test an npm package in an output directory. Once built, you only need to npm publish the output directory to distribute it to Node.js users.
For more details, see https://github.com/denoland/dnt

Related

Why is Node.js required for Angular?

Why is Node.js required in order to use Angular?
In other posts, people say that it isn't required, and that it's only needed if you want server-side code. But the Angular documentation specifically states the need for Node.js in the "Getting Started" section. Why exactly is Node.js required? What if I want to use .NET Core as my server side back-end?
Straight from the Angular site:
Prerequisites before you begin, make sure your development environment
includes Node.js® and an npm package manager.
Node.js Angular requires Node.js version 8.x or 10.x.
To check your version, run node -v in a terminal/console window.
To get Node.js, go to nodejs.org.
Angular does not need Node.js directly and it is not mandatory to use Node.js. But you will need Node.js for all the build and development tools.
For an example these are few reasons that you need Node.js for building an Angular app,
npm (node package manager) comes with Node.js by default and it allows
you to manage your dependencies. So, you don’t have to worry for
operations like adding a dependency, removing some, updating your
package.json.
npm gives you angular cli or ng cli (angular command-line interface) which is a great tool for building your application easily
Node.js allows you to spin up a lightweight web server to host your application locally in your system.
You do need Node.js to develop Angular applications. All the tools you will run, while developing it, uses Node.js to run, like npm and the Angular CLI itself.
Node.js will serve your application on your machine. It has nothing to do with the server-side of your application, which can be any language you want.
Node.js allows you to spin up a lightweight web server to host your application locally in your system
NPM comes with node.js by default - used to manage dependencies
so you don't need to worry about adding/removing dependencies
(to node_modules folder, package.json/package.lock.json files)
NPM gives -> Angular CLI which is used to initialize,develop,scaffold & maintain angular application directly from command shell. It uses webpack for bundling your applications.
Also Angular uses TypeScript but browser understands Html & JavaScript only -> Typescript is transpiled into JS.
Angular CLI does all these behind the scene.

How to build native nodejs modules for launchui?

I'm building an app using proton-native.
it uses native modules written in C++, for example, keytar.
Proton-native uses a tool named launchui to package nodejs app as an executable. It's basically simple wrapper for nodejs with the following structure on windows:
- myapp.exe
- node.dll
- app/
- - main.js
- - node_modules/
- - - - keytar/
Native modules (node addons) does not work by default for such constructions because node-gyp tool links them against node.exe.
The usual approach is to run something like electron-rebuild, which would compile native modules to a version of node incorporated by electronjs.
However, In case of launchui there are no tools for that yet.
Could someone skilled in node-gyp or C++ linking explain what whould be the best approach to properly re-build native modules for launchui? I keep getting The specified procedure could not be found after running electron-rebuild and trying to run the app.
I have used dependencywalker to analyze current dependencies of the keytar.node and it shows that it depends on node.exe, however it should depend on node.dll.

Efficiently Bundling Dependencies with Electron App for Distribution

I am trying to figure out an effective way to bundle and distribute various dependencies (node modules and/or "client"-side scripts and framework like Angular) with my Electron App.
Although the basic approach of npm install module-name --save works well for development, it is not so good in the end when it comes to minimizing the size of your app and using minified resources at runtime. For instance, virtually all npm packages (including node modules) come with a lot of "extra baggage" like readmes, various versions of components (minified, not minified, ES2015, no-ES2015, etc). While these are great for development, all these files have absolutely no need to be included in the version you will be distributing.
Currently there seem to be 2 ways to sort of address the problem:
Electron Builder recommends using 2-file package.json system.
Any dependency that is used during development only should be npm-installed using --save-dev and then prunning should be used when building the app for distribution.
In that regard I have several questions:
I am not quite sure why there is a need for 2-file package.json system if one can install dev-only modules/ dependencies with --save-dev and then use pruning during the actual app build/compilation?
Regardless of which method above is used, you still end up with full npm packages in your app, inclduying all the miscellaneous/duplicated files that are not used by your app. So how does one "prune" so to speak the npm packages themselves so that only the actual files that are being used at run-time (like minified scripts) get included?
Will using Bower for "client-side" packages (like AngularJS 2, Bootstrap, jQuery, etc.) and using npm for node modules (like fs-extra) be a better option in as far as separation of concerns and ease of bundling later?
Could WebPack be used to produce only the needed files, at least for the "cient-side", so that only real node modules will be included with the app, while the rest of it will be in the form of web-pack compiled set of files?
Any practical tips on how this bundling of dependencies and distribution should be accredited out in practice? Gulp-scripts? Web-pack scripts? Project structure?
Thank you.
I am still in the learning curve of adopting the best practices in code deployment. But here is my starting list of what is recommended.
Yes, npm install --save-dev is the first easiest thing to isolate dev and build specific packages. This includes gulp/grunt/webpack and its loaders or additional packages. These are used only for building and never in the code that actually is run. All packages used by the app should be installed with npm install --save so that it is project level available. So, in production, you would no npm install --production in machines which will not install dev packages at all. See What's the difference between dependencies, devDependencies and peerDependencies in npm package.json file? for more info.
While the original recommendation was to use bower for client side and npm for server side, both can be installed using npm too. After all, both does the same job of managing the packages and dependencies. However, if web pack is used, it is recommended that npm is used for client side dependencies also.
package.json should be thought of managing the dependent packages only and not for building. For building and picking only the required files, you need task runners like gulp/grunt or bundlers like web pack.
While gulp/grunt is very popular for build automation which includes bundling all dependent javascript in file and minifying them in to one file, webpack/browserify is a better option as it supports module import. Module import is intuitive way of require one module in another in node js type of coding
var util = require('./myapp/lib/utils.js') This is powerful way of mentioning the required dependencies in the code. The web pack builder runs like gulp as build process. But instead of looking through html file for all js files, looks at starting js file and and determines all dependent code mentioned by the require statements recursively and packages accordingly. It also minifies the code. It also loads css and image files in one bundle to reduce server trips. If needed, some modules can be configured to be loaded at runtime dynamically further reducing page load. NPM vs. Bower vs. Browserify vs. Gulp vs. Grunt vs. Webpack discusses this at length.
Webpack can be used to bundle client side app optimally while server side need not be bundled or minified as there is no download.
In web pack, though you can mention dependent modules with lib file path, the recommendation is to npm install all dependencies and mention the module name. For example if you have installed jquery, instead of giving path like /libs/jquery.min.js, you can mention as 'jquery'. Webpack will automatically pull the jquery lib and dependencies and minimise it. If they are common modules, it will be chunked too. So, it is better to npm install dependent packages instead of bower install.
ES2015 provides lot of benefits during coding time including type checking and modules. However all browsers do not yet support the spec natively. So you need to transpile the code to older version that browsers understand. This is done by transpilers like Babel that can be run with gulp. Webpack has in-built babel loader so web pack understands ES2015. It is recommended to use ES2015 module system as it will soon become the defacto way of coding and since there is transpiler, there is no worry of this not being supported in IE8/9.
For project structure you could have
server
client
src containing js files
dist containing html and build files generated
webpack.dev.config.js and webpack.prod.config.js can be at root level.
I have found that this area is an ocean and different schools of best practices.This is probably one set of best practices. Feel free to choose the set that works for your scenario. Look forward for more comments to add to this set.

Why do we have install Node.js for Angular 2.0?

I started a tutorial on Angular 2.0, the first step in setting up the workspace is installing Node.js and NPM.
Why do we have install Node.js for Angular 2.0?
I don't remember doing this for angular 1.X.
Technically, Node.js and NPM are not needed to do Angular2 work. It does ease things though. Here's the main reasons I speculate are behind this choice:
CLI: Since a while now the de facto way to build and develop new Angular apps is to use the CLI tooling which relies on Node and NPM as well.
TypeScript: Examples are .ts, and you need to run a compiler step to get them into .js, which can be done on-the-fly easily with Node.js and NPM (plus it's a way of easily getting typing files);
Web Server: Serving your Angular SPA from a "real" albeit light web server prevents probably some nasty issues that come with checking your site using file:// links.
The Quickstart guide itself actually continues to mention some more concrete reasons as well:
Here's what these scripts do:
npm start - runs the compiler and a server at the same time, both in "watch mode"
npm run tsc - runs the TypeScript compiler once
npm run tsc:w - runs the TypeScript compiler in watch mode; the process keeps running, awaiting changes to TypeScript files and re-compiling when it sees them
npm run lite - runs the lite-server, a light-weight, static file server with excellent support for Angular apps that use routing
npm run typings - runs the typings tool separately
npm run postinstall - called by npm automatically after it successfully completes package installation. This script installs the TypeScript definition files defined in typings.json
You can also have a look at the Quickstart source and further dive into where NPM is needed.
Footnote: there's a similar question about needing Node.js for AngularJS (1.x).
Because Anglar2 is based on Typescript, Web Components and ES6 which need compilation for performance and broader browser support. Typescript is compiled to ES5 JavaScript and the other features require shims for backwards compatibility.
Since Typescript is a superset of JavaScript, and it's compiled to JavaScript anyway, you can write your code in plain JavaScript but it's not recommended.
For a more detailed explanation check out these videos on YouTube
Why Typescript
Instalation steps
NodeJS gives you the tool npm that allows you to download libraries and packages you would use in Angular 2. From the shell you can go to your folder and type npm install to install dependencies you need to have installed to get your angular project going. It will make it easier for you! If you want a complete starter kit go to https://github.com/buckyroberts, you can fork or download the zip with all the starter files to get you going :)
You do not need to use Node anywhere in production to use any front-end JavaScript framework, whether it is jQuery, AngularJS, ReactJS, Angular2, etc.
Angular2 can be used in isolation but to get and feel better development environment, angular2 should be used with nodejs and npm. Some of the nodejs modules helps you in web development.

How to package & deploy Node.js + express web application?

I am new to Node.js programming and I have recently created a sample working web application using (express, backbone & other complimentary view technologies, with mongoDB). Now i am at a point where I want to deploy the same on a staging environment and I am not sure how to package this application and distribute the same. [I can take care of mongoDb and setting it up seperately]
I am from Java world and in there we create jars for reusable libs and war/ear packages for web applications which is deployed in a servlet container. Now in this case since node.js itself acts as a web container as well, how do i package my webapp?
Is there any standard format/guidelines of packaging node webapps built using express? (Is there a similar jar/war packaging systems for node apps?)
How do I deploy it once packaged? Would it become an exe, since it is also its own container?
PS: As of now I am thinking of just manually copying all the required source files into the staging environment and run npm commands to download all dependencies on that machine and then use 'forever' or some other mechanism to run my server.js. (Also, add some sort of monitoring, just in case app crashes and forever fails) I am not sure if that is the right way? I am sure there must be some standardized way of addressing this problem.
Deploying Node.js applications is very easy stuff. In maven, there is pom.xml. Related concept in Node.js is package.json. You can state your dependencies on package.json. You can also do environmental setup on package.json. For example, in dev environment you can say that
I want to run unit tests.
but in production;
I want to skip unit tests.
You have local repositories for maven under .m2 folder. In Node.js, there is node_modules folder under your Node.js project. You can see module folders with its name.
Let's come to the grunt part of this answer. Grunt is a task manager for your frontend assets, html, javascript, css. For example, before deployment you can minify html, css, javascript even images. You can also put grunt task run functions in package.json.
If you want to look at a sample application, you can find an example blog application here. Check folder structure and package.json for reference.
For deployment, I suggest you heroku deployment for startup applciations. You can find howto here. This is simple git based deployment.
On project running part, simply set your environment NODE_ENV=development and node app.js. Here app.js is in your project.
Here is relative concept for java and nodejs;
maven clean install => npm install
.m2 folder => node_modules(Under project folder)
mvn test => npm test(test section on package.json)
junit, powermock, ... => mocha, node-unit, ...
Spring MVC => Express.JS
pom.xml => package.json
import package => require('module_name')
There is no standardized way, but you're on the right track. If your package.json is up to date and well kept, you can just copy/zip/clone your app directory to the production system, excluding the node_modules.
On your production system, run
npm install to install your dependencies, npm test if you have tests and finally NODE_ENV=production node server.js
Some recent slides I considered to be quite helpful that also include the topic of wrappers like forever, can be found here.
Hope this might be helpful for somebody looking for the solution,Packaging of Node js apps can be done using "npm pack" command.It creates a zip file of your application which can be run in production/staging environment.
Is there any standard format/guidelines of packaging node webapps
built using express? (Is there a similar jar/war packaging systems for
node apps?)
Yes, the CommonJS Packages specification:
This specification describes the CommonJS package format for
distributing CommonJS programs and libraries. A CommonJS package is a
cohesive wrapping of a collection of modules, code and other assets
into a single form. It provides the basis for convenient delivery,
installation and management of CommonJS components.
For your next question:
2. How do I deploy it once packaged? Would it become an exe, since it is also its own container?
I second Hüseyin's suggestion to deploy on Heroku for production. For development and staging I use Node-Appliance with VirtualBox and Amazon EC2, respectively:
This program takes a Debian machine built by build-debian-cloud or
Debian-VirtualBox-Appliance and turns it into a Node.js "appliance",
capable of running a Node application deployed via git.
Your webapp will not become an exe.
few ways to approach this:
Push your code into Git repository, excluding everything that isn't your code (node_modules/**), then pull it in your staging environment, run npm install to restore all dependencies
create an NPM package out of it , install it via npm in your staging environment (this should also take care of all of the dependencies)
manual copy/ssh files to your staging environment (this can be automated with Grunt), than restore your dependencies via npm
I used zeit's pkg module. It can create cross platform deliverables for linux/win/macos. Actually used it in production and works fine without any issues.
It takes in all the js scripts and packages it into a single file.
The reason I used it is because it helps in securing your source code. That way in production at customers environment they will have access to application but not the source code.
Also one of the advantages is that at production environment, you do not actually need to have the customer install node.js as the node binaries also get packaged inside the build.
https://www.npmjs.com/package/pkg

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