first, the "facts" that I know:
reactJS is frontend framework, after compiling it'll generate a bundle of html/js/css files that can be recognized by modern browsers, so the browser straightforward request the web host server for these static html files ;
nodeJS is a server-side environment, or sometimes people call it a backend framework, browsers don't understand nodeJS but have to request the web host server to interpret it and to send back the html response.
according to wiki, npm is a package manager for the JavaScript programming language. It is the default package manager for the JavaScript runtime environment Node.js.
my question is:
is my understanding correct
why reactJS also using npm and includes node_module, does it have something to do with nodeJS
Javascript is the programming language used in both Node.js and in the browser, but that's about as far as the similarities goes. Node uses the V8 engine, which is the same running in the chrome browser.
Even though they use the same engine, they are quite different. They both have plenty of APIs - most notably, the browser has the DOM (which allows you to render stuff to the screen). In Node.js you do not have the DOM, but there are other APIs, for accessing the filesystem for instance.
Since both are running JavaScript, you can try to run the same program both in node and in the browser, but it will sometimes fail. React is a front-end framework which uses the DOM, so if you try to run React in node, it will crash because in Node there is no DOM (Node has no screen to render to). If you try to run a program suited for Node.js in the browser, it will crash if it uses some Node-specific API.
The confusing bit is that npm is a package manager for JavaScript, not necessarily node (even though node is in the name..). Therefore, we can use npm also for web applications. (If we do, we need to use a bundler like webpack though).
Some npm modules might work both in the browser and in node, but some will only work on one of them. If the npm module requires some platform-spcific API (DOM for the browser for example) then it will not work for the other platform.
Hope that clears things out! I understand that it's a bit of a mess..
Related
I understand that when we talk about the frontend we're talking about files being served to the browser of the person accessing my page. So, frontend javascript libraries are only javascript code that is being sent from my server to the browser.
So far everything is fine, what I don't understand is why npm has repositories for frontend libraries. Let's take this Leaflet example, I can install this library with npm using npm install leaflet -s. But what would be the purpose of doing that? I see that if I open Visual Studio Code and I declare this library with const leaflet = require('leaflet') then I can see its functions and documentation in a more clear way on the suggestions after typing leaflet.... I don't think that's the purpose of installing a library like Leaflet on Node.js though (since it works only on the frontend). What am I missing? Why would anyone install frontend only libraries on Node.js?
There are likely other reasons, but this is they reason I've done it and the reason I've seen other people do it: Many people use Node.js tooling to bundle/build webapps, so you might install your frontend dependencies, and then use rollup or webpack or browserify or TypeScript tooling or whatever to bundle it into a single .js file. Since you're likely already installing the tooling with npm, installing the libraries also with npm means you don't need some other tool to do it.
Additionally, people also use npm to install libraries for electron apps, cordova apps, React Native apps, etc. And these things can all use frontend libraries because they basically have a web view embedded. (To be honest, I'm not sure that's the case with React Native because I've never used it, but I assume it is.)
Since you mention Leaflet specifically, here is an example of someone using npm to install leaflet, and then using browserify to make it so that they can basically write Node.js code (including require('leaflet') and run it in the browser.
This may be a dumb question, but is the default react app (created using npm create-react-app my-app) using node.js? I am confused because in my web development class at university, I had to download node.js to create react applications. However, I didn't have to do anything like creating a server or initiating a node.js file, which is described in w3school's node.js tutorial. Because of this, I found out that I don't even really know what node is used for, besides downloading packages like redux and whatnot.
create-react-app uses node.js for all of its dev tooling. Likewise, a lot of the tools you'll use in the React ecosystem (like webpack, prettier, npm), all run on top of node.js as well).
You'll most probably build your react app to a static file, in which case the production output will not require node.js, it will be html and javascript assets that can be served directly to a client.
Hope that helps! Let me know if you have other specific questions
Node.js is used for server-side while React.js is for the front-end part. So, no, you don't need Node.js.
Under development mode, yes. Create react app runs NodeJs with Webpack Dev Server to allow you get feedback when modifing files, start or stop the server.
I have been using webpack to build a server side app using express. This code is harder to debug since I don't have the immediate comfort of a web browser and if I use something like VS Code to debug, it won't accept breakpoints inside request handlers when using source maps. Besides it takes no time to compile if I just stick to Node compatible JS and skip all transpiling and whatnot. Further, if I use treeshaking, I can reduce the size, but what is the point of that when it is running on the server (no client will ever download it).
My point is that I don't see why one would want to create a bundle of server side code if the server don't have any issues with memory or other limiting factors. It's easier to read, takes no time to compile and is easier to debug.
So a question. Is it ok to have the server app as an npm package and deploy that? Is that what is common or what do people do?
The project my team works on is a TypeScript monorepo that includes a web application and server-side daemon processes. We use webpack for producing build artefacts for all targets.
I've read some posts saying there's no point using webpack server-side because it was designed for web (obv), and I can understand that point of view.
However, even if our code was JavaScript and didn't require any transpiling, we'd still use webpack for the server-side. I want a single, minimal set of files and no node modules to deploy to the servers.
Size itself doesn't matter that much for server side (though every bit helps), but running 'yarn install' on servers is out of the question IMO.
For my understanding, node.js is a javascript-engine which is running javascript-code without using a browser(window-global). You can use javascript on a server. But I saw now a lot of tutorials(react, angular, vue etc.). In every tutorial, I have to install something with npm. I can follow there are several dev-tools which I can use on my local machine to minimize my javscript-files or compile sass to css. But in the end, when I put my files on a webserver, I just have normal javascript-files, css-files etc. No node.js code in it, right?
My question is: React, angular, vue.js etc. are written in just normal javascript without node.js right? The reason why I use npm ist just to install every dependencies with one command, right?
A question more: Is there an any recommended order to learn all these frontend-development stuff? There are so much words I have to google it: angular.js, react, vue.js, vanilla.js, typescript, backbone.js, bower, grunt, webpack, yarn etc... I dont know where I start, so I look into few tutorials, but everytime I go through these tutorials, there is a new word(technology) I have to research.
I think you're getting your terminology a little muddled.
Node.js is a JavaScript runtime, built on Google Chrome’s V8 JavaScript engine. However, that is not to say that Node programs are executed in a browser. They aren’t. Rather, the creator of Node (Ryan Dahl) took the V8 engine and enhanced it with various features (such as a file system API and an HTTP library) to create a program we can use to execute JavaScript on our computers.
Node comes bundled with a package manager called npm which you can use to install packages (such as React and Angular) from the npm registry. These packages are indeed written in normal JavaScript (or a language that compiles to JavaScript, such as TypeScript).
The reason why I use npm is just to install every dependencies with one command, right?
Kinda. You can certainly use npm to install dependencies. However, it does a lot more that that. For example you can use npm scripts to carry out various build tasks, or you can create a package yourself and use npm to publish it to the registry.
A question more: Is there an any recommended order to learn all these frontend-development stuff?
As with everything, it depends. What are you trying to build? It's relatively pointless to learn about Node, npm, React and Angular if you are attempting to build a simple static website. If I were you, I'd define a clear goal and set about learning the technologies you'll need to reach that goal. Saying that, if you are doing anything with front-end development, learning about npm will be a good use of your time.
Here's an article by way of further reading that explains things a little more: https://www.sitepoint.com/an-introduction-to-node-js/
My understanding is that AngularJS including Angular2 is a client-side framework, while Node.JS is a server side platform. They should not cross. But all Angular2 tutorials I found use Node/NPM. Why is that?
Because npm is a package manager for packages written in JavaScript, and JavaScript can run both on client and server side. In other words, frontend and backend applications can both benefit from packages. Many development tools also use node as an underlying process (e.g. Jest-cli).
I would suggest you to use angular2 only on client side. The performance of angular2 really shines when it comes to handling view containers over regular server side codes. On the NodeJS side, I would recommend using es6 features. Which has revolutionised how you can not only code, but also performance.
The reason you see most tutorials using npm is because they are either using TypeScript or a build tool that uses Node to convert to ES5 or build your project.
However you can still build Angular2 apps using the sfx version (self-executing bundle) of Angular2 and using ES5 syntaxes without having to use node or npm. Here is a blog post that shows how to do that
http://blog.thoughtram.io/angular/2015/05/09/writing-angular-2-code-in-es5.html
Angular2 is a front-end framework but a lot of tooling that assists in building Angular2 applications are available via NPM.
If you want a package manager that's geared specifically to front-end development I suggest JSPM. It supports front-end modules of various formats (ie AMD, CommonJS, UMD), handles transpiling out of the box, and can be used as a build tool to concatenate/minify your application code.
You'll still need NPM for many other utilities and you'll need a back-end server for testing (I recommend live-server).
As far as the back-end is concerned. One of the Angular2 dev teams is working on a Node/Express extension that supports isomorphic rendering of JS. In short, it pre-renders the view on the server so the user can interact with it in the browser while the app loads in the background. The start time of launching a fully-featured SPA will still be kind of slow (relatively) but perceived speed will be instantaneous.