I made a Javascript file. Let's say the contents of it are this:
let myCoolAlert = (str) => {
alert(str)
}
// in a different js file (SO doesn't allow you to cross-file as far as I know
myCoolAlert('Hello World!')
I already hosted the JS file on a CDN. Now, I want it to be automatically hosted locally by whoever installed it if you install it via NPM. Is there a way to do this?
Also, I noticed that to do the same using Socket.io, you have to pass Socket.io to the HTTP/HTTPS server you created. Will I have to do this also? (I would prefer not).
Thanks!
Edit:
I am trying to make a better alert system (like sweetalert). I coded it in Javascript and works when using it through the CDN. However, I also want users to be able to install this via NPM (kind of like SweetAlert? I am not sure about that last statement however because I do not use it). When they install it with NPM, it's obviously going to be useless because it is for the browser. However, I want them to either:
Automatically have the source code needed available at a URL like localhost:3000(or server name)/betterAlert.js and be able to use that URL as a script in the HTML files
OR, have the user pass the HTTP or HTTPS server they created to the module (like socket.io does) and have it automatically host it from there.
Please note:
The code I am trying to bundle is native to the web. Will it still work with a bundler like webpack?
Is this possible? Thanks again.
To bundle client-side code and publish it through NPM you'll need to do a couple things: learn how to package and publish modules, and write some code that can be consumed. This means using module.exports or export to expose your library, depending on whether you want to use CJS or ESM. The consumer of your library can usually be assumed to be using Webpack, Fuse, Rollup, or some other bundler which knows how to deal with modules.
You can also use a tool like Rollup yourself to build and bundle up your library for different targets and apply various transformations to it (example from my own library boilerplate). Using a bundler like this makes more and more sense as your library inevitably grows larger.
Using modules like this rather than distributing through a CDN or in some other way that puts your library code on the global/window object is generally better for consumption in complex apps, large apps, and/or apps already being built with tools like Webpack (so, anything written in React, Angular, Vue, etc.). But having a CDN distribution is still a good idea for something like your library, since it may well be used by people building sites with jQuery and vanilla JS.
Related
When we talk about JavaScript vanilla it's frontend programming language; It needs a webserver like IIS, Apache or nginx etc to deliver the content to a client when requested. After that, JavaScript runs on client browser, but every video or article I found said we need to install node.js to make this work. What I know about node.js is its a runtime environment to make JavaScript work outside the browser; like for a backend api or regular desktop application.
Here is my question:
Why do we need to use Node.js if our target is to deploy a frontend webapp that's gonna run on the client browser?
You don't have to install and use Node to make frontend applications, but it can help a lot, especially in large projects. The main reason it's used is so that script-writers can easily install, use, and update external packages via NPM. For a few examples:
Webpack, to consolidate multiple script files into a single one for production (and to minify, if desired)
Babel, to automatically transpile scripts written in modern syntax down to ES6 or ES5
A linter like ESLint to avoid accidental bugs and enforce a consistent code style
A CSS preprocessor for Sass that can turn (concise) Sass into standard (more verbose) CSS consumable by browsers
And so on. Organizing an environment for these sorts of things would be very difficult without NPM (which depends on Node).
None if it is necessary, but many find that it can make the development process much easier.
In the process of creating files for the client to consume, if you want to do anything more elaborate than write plain raw .js, .html, .css files, you'll need something extra - which is most often done via NPM.
It's only for extra support during development, and ease of installing libraries. almost like an extra IDE / helpful editor
for example you might want to see changes you make on your HTML and frontend javascript code, without having to refresh the preview browser. node will provide a package that does that...
it also helps install and use libraries easier. for example, if you want to add a library like bootstrap to your frontend, rather than searching around and downloading the files... but if you use node project, you can simply use npm install bootstrap that will automatically download the lastest version from the right source.
that's all
there is another unfortunately named post that appears to be asking the same question, but is, in fact, not. this is actually asking how to do what I asked specifically.
I have a situation where we can't use NPM. not being as familiar with JS as I'd like to be, I want to use the vueDataTables library, but don't know how (or if) I can bypass the NPM-only install instructions and just download, link, and use it locally.
more generally, how would one use an NPM installed library when you don't have or can't use NPM and need to link the library locally?
You can download the zip build file, and add it to your source code, then you can import it using the local path. For example
import DataTables from './lib/vuewthing/dist.js
Or add the source files from that library and point to them, but that will slow down your build times and performance.
If they don't have a downloadble build, you can clone it, and build it, and then paste the built files to your source.
The project I'm currently working on (Java/JSP) currently uses no package manager to manage its JavaScript dependencies.
The used libraries are just committed under version control, and referred as such from the JSP pages...
I would like to evolve to a workflow were we would use a package manager (e.g. yarn), and later on eventually also webpack to further optimise the build.
I would like to do this in a phased approach. As I have little to none experience with such a frontend workflow, I have some questions:
Would it be weird to just start with defining the used libraries in a package.json file, and use yarn to manage to package?
yarn will then fetch the modules and store them in the node_modules folder.
Is it bad practice to refer to the scripts in that node_modules folder directly from within the JSP files?
Example
package.json:
"dependencies": {
"jquery": "^3.4.1"
}
app.jsp:
<script src="node_modules/jquery/dist/jquery.min.js"></script>
Yes, that's completely ok. It's the way we normally initialize frontend projects (probably sometimes, some higher-level script does it for us but still). Just run npm init.
Oh yes, that's quite bad. Most probably, it simply will not work. If you want to load something directly on a page, you need a cdn version.
To be honest, having a package.json is not that useful without a building tool like webpack, gulp or grunt.
UPD:
Regarding why loading things directly from node_modules might hurt:
A lot of modern JS packages (like, for instance, React) use modules that are not implemented yet in any browser or ES5+ syntax which is supported only by some browsers.
This way, you may load React directly but it will crash in any browser with something like import is not defined.
Basically, a lot of modern packages expect you to either have a building tool or use cdn version.
Honestly, I don't know how many packages let you seamlessly load things directly from node_modules.
So, in your particular situation, I'd say that if particular packages you use let you do so & are shipped with browser-compatible version, you can just go ahead & do it this way.
Nevertheless, I see it highly possible that sooner or later you will face a package that will not let you to include it this way (or worse: it will, but will crash some browsers that don't support latest JS features/introduce other nasty bugs in your app).
Hopefully, at this stage, you will already have the building tool configured.
Bonus:
Relatively recently some browsers started to support modules!
There are even tools like snowpack that do something particularly similar to what you are looking for.
Even though, you still need to be very careful with this. Direct inclusion of lodash.js, for instance, will generate 640 GETs (check out this article -> "Libraries" section).
NPM packages are meant to be run with Node, not in a browser. You would need to serve a browser-friendly version, using something like webpack or browserify.
Once npm and nodejs installed, it is possible to easily use a module by running
npm install module
and then using the js require() function. I assume the source code stored somewhere on my computer will then be loaded. But what if I want to use javascript functions of this module within a client's browser ? With a bit of work, I can probably end up finding some file on my disk, or maybe on the web, with the source code I need inside it. My question is : is there a standard process that gathers all the dependencies of a given module, so I can serve them on a client website ? Or do I totally miss something and things are suppose to be done in an entirely different way ?
If the library is published as standard javascript modules, you can load it directly into the browser, as in this example:
<script type="module">
import { html, render } from '/node_modules/lit-html/lit-html.js';
render(html`<span>Hello, world</span>, document.body)
</script>
The unpkg service provides a useful tool to automatically transform module specifiers to absolute URLs, you just have to add the ?module query string:
import { html, render } from 'https://unpkg.com/lit-html/lit-html.js?module';
If, however, as is (unfortunately commonly) the case, the library is published as CJS modules, you'll need to use a module bundler. I'm partial to rollup. To roll cjs modules up in your bundle, make sure to install and use the rollup-plugin-commonjs plugin.
There are a variety of tools available to merge your dependencies into a single file that can be consumed by a web browser. Such tools are typically referred to as "bundlers".
A few popular examples include:
Webpack
Browserify
Parcel
This list is not meant to be comprehensive or even a recommendation of which tool to use.
I am in the process of converting an existing Rails 3.1 app I made for a client into a Backbone.js app with the Rails app only as a backend server extension. This is only a personal project of mine, to learn more about Backbone.js.
While setting up Backbone.js (using Backbone-on-Rails), I noticed I have some dependencies (like backbone-forms) that come from external sources and are frequently updated.
I've grown accustomed to using Bundler to manage my Ruby gems, but I haven't found anything similar for JavaScript files. I'm wondering if there is any way to do the same for Javascript (and possibly css) files.
Basically I can see three possibilities to solve this issue:
Simply write down all the sources for each JS file and check these sources from time to time to see what has changed.
Use some kind of existing "Bundler for Javascript" type of tool, I've been looking for something like this but have yet to find anything (good).
Since most of these JS files will be coming from Git anyway, use Git to get the files directly and use checkout to get the latest version from time to time.
I prefer the last option, but was hoping on some more input from other people who have gone this route or preferred some other way to tackle this issue (or is this even an issue?).
I figure the Git way seems easy, but I am not quite sure yet how I could make this work nicely with Rails 3.1 and Sprockets. I guess I'd try to checkout a single file using Git and have it be cloned in a directory that is accessible to Sprockets, but I haven't tried this yet.
Any thoughts?
You don't mention it in your alternatives, but ideally you should use something like Maven to manage your dependencies. Unfortunately, there are no public repositories for javascript files. This discussion lists some other options which might be of help to you: JQuery Availability on Maven Repositories
For now I've settled on using the Git solution combined with some guard-shell magic.
The steps I follow:
Create a dependencies directory somewhere on your local drive
Clone the repositories with javascript (or css) files you want to use in the app
Set up a custom guard-shell command to do the following:
group 'dependencies' do
guard 'shell' do
dependencies = '~/path/to/dependencies/'
watch(%r{backbone-forms/src/(backbone\-forms\.js)}) {|m| `cp #{dependencies + m[0]} vendor/assets/javascripts/#{m[1]}` }
end
end
Place the Guardfile at the root of the app directory
It takes some time to set things up, but after that, when you have the Guard running, and you pull changes into your dependencies, the required files are automatically copied to your application directory, which are then part of your repository.
It seems to work great, you need to do some work for each new file you want to include in the asset pipeline, but all that is required is cloning the repository in your dependencies directory and adding a single line to your Guardfile, for example for the backbone-form css:
watch(%r{backbone-forms/src/(backbone\-forms\.css)}) {|m| `cp #{dependencies + m[0]} vendor/assets/stylesheets/#{m[1]}` }
Also, the reason I added this Guard to a group is because I keep my dependencies outside the main application directory, which means guard normally doesn't check my dependencies directory. To make this work, I start up my main Guard processes using bundle exec guard -g main and use bundle exec guard -w ~/path/to/dependencies -g dependencies in a new terminal window/tab to specify the -w(atchdir).