Am I correct in understanding that Webpack transforms everything you have into JS code only? So that even if you have CSS, it will be turn into JS (in a bundle) as long as you have the correct loader?
Loaders can transform files from a different language like
CoffeeScript to JavaScript, or inline images as data URLs. Loaders
even allow you to do things like require() css files right in your
JavaScript!”
Loaders won't convert CSS into JavaScript but it will allow you to import CSS files right from your JavaScript file. For e.g. you have components based application architecture and each component has it's own CSS, you can load css right from component's JS file.
Like this (in your app.js)
import styles from './app.css';
OR more generic
import './app.css';
From Official site
Loaders can transform files from a different language (like
TypeScript) to JavaScript, or inline images as data URLs. Loaders even
allow you to do things like import CSS files directly from your
JavaScript modules!
Example
For example, you can use loaders to tell webpack to load a CSS file or
to convert TypeScript to JavaScript. To do this, you would start by
installing the loaders you need:
npm install --save-dev css-loader
npm install --save-dev ts-loader
And then instruct webpack to use the css-loader for every .css file and the ts-loader for all .ts files:
Related
I'm working on a Vue component library built via VueCLI (and using Storybook Js, Bulma, and Buefy) and I am having issues consuming the CSS downstream. Specifically when I import the CSS file from my package, I am getting Webpack errors with referenced images.
For example, in my upstream src scss files I have a file called "notice-badge.scss" and am referencing background images like so:
.notice-badge img {
background-image: url('#/assets/img/warning-dark.svg');
}
and my src directory structure looks like:
my-app/
|--src/
|--assets/
|--scss/
|-- notice-badge.scss
|--img/
|--warning-dark.svg
|--fonts/
|--vue-components/
and I build the packages with this command which produces no errors.
vue-cli-service build --target lib --name my-ui-components ./src/index.ts
This outputs my JS, a CSS file, and 2 directories (img and fonts) into my "dist" directory. The images listed in my errors are infact inthere.
So over in another Vue cli app (and later Nuxt) I will be importing the CSS file and Vue components but I am getting a "can't resolve" error on that warning-dark.svg file:
Can't resolve /img/warning-dark.a45b259b.svg in /Users/myname/sites/my-app/ui-components/dist. My package also contains font awesome font files too (a business decision to include this all up stream)
So how can I get my downstream Vue CLI app to resolve the images and fonts referenced inside my node_modules dir?
You have (at least) 3 options:
Inline the images/fonts as data URLs.
Use a relative path in the output and require apps that install your package to move the image directory to the same path as the built CSS file.
Don't ship built CSS, but instead source SCSS files. That way file loading/moving can be handled with WebPack configuration in the app that uses it (using file_loader. You can include example configuration in your package to make this easier.
If you're writing a Vue component library, it probably makes most sense to use method 3. However from your description it seems like this may not be an option (the business decision you mention). Method 2 might be viable but I didn't try it nor seen someone else suggest it.
Inline
This method probably is easiest and has best performance. If your other SVGs are similar to the examples, it seems like they should all be relatively small files. There's few reasons for a component library to ship big images, so this might be sufficient for your use case.
If you're using WebPack 5, you can inline assets using "Asset Modules".
module: {
rules: [
{
test: /\.svg/,
type: 'asset/inline'
}
]
}
If you tried this, you may have run into the following problem.
Since Sass implementations don't provide url rewriting, all linked
assets must be relative to the output.
If you pass the generated CSS on to the css-loader, all urls must be
relative to the entry-file (e.g. main.scss).
If you're just generating CSS without passing it to the css-loader, it must be relative to your web root.
You can try replacing url('#/assets/img/warning-dark.svg') with url('../img/warning-dark.svg') (or whatever the path relative to the entrypoint is). Does it now properly inline them?
Let's say I have a few external javascript files (libraries, if you prefer to call them that way). Those files haven't been adapted to any of the "modern" JS functionalities, meaning that I can't import them like I'd do with some of the most common libraries nowadays (lodash, axios, etc...). The files in question have been always used as old-style import-and-use libraries (<script src="foo.js"></script>).
How can I make Webpack pack (concatenate) all those files and inject them in the head of my index.html, right before my actual bundle?
You can download 'foo.js' manually and add it to project repo. Imagine like you have a folder called 'external-libs' and you can simply import foo.js as something like following
import '../../external-libs/foo.js';
This will be enough for Webpack to append the content of foo.js to your final bundle.
I'm looking for a way to watch changes on files (sass files precisely) and execute a loader on other files (js files) with webpack.
The goal is to detect sass changes and recompiling all the javascript files with the babel-loader, because they might import it through the styled-jsx plugin.
I'm stuck in the "loader" concept and can't figure out how to get other files when testing for /.scss$/
You don't need to do anything by yourself if you using scss modules with webpack (more about module concept in the webpack docs.
What webpack does - it starts at entry point (you can specify one or multiple entrypoints, if you don't, default src/index.js would be used). And then builds dependency trees between modules (which can have any file extension as long as there's a specific loader that can turn file into module). Webpack then watches all files and rebuild all modules that have a dependency on changed file. So, if you import the .scss file in, let's say, your entrypoint
import './styles.scss';
// ...
It would rebuild automatically when styles.scss changes
You need to import your .scss file(s) under one of your .js files so that webpack actually picks up the changes.
Then, all loaders you have configured will be applied automatically based on which file type they should target.
I am trying to structure javascript files in a project. I have used NPM to manage the modules and planning to use Grunt to concatenate and compress the js and css files for deployment.
I am currently using the following structure
-[project root]
-- [node modules] :packages such as requirejs, jquery, semantic-ui etc using npm
--[war]
---[Dev]
----[css] multiple css files from modules (Question 2:?)
----[js] multiple js files from modeuls (Question 2:?)
- Gruntfile.js :for concatenate and compress
---[Production] -
----[css]:This is where the compressed and concatenated css files are kept
----[js] :This is where the compressed and concatenated js files are kept
Question 1: Is the above approach to structure the project correct ? Any other recommendations which allows to manage the packages, dev and production files.
Question 2: Can NPM or another tool allows me to pick up the js and css files from the [node modules] folder and place them to (dev>>css or dev>>js) folder ? If am doing this manually how do I track the versions ? Seems like I am missing something here, there must be a better solution.
Suggestions/recommendations/comments are much appreciated.
Thanks
The question is a bit too wide for SO format, but in general your structure is good. Instead of copying files from node_modules, you have your own JavaScript files under js and you import/require them to your own files.
//foo.js
//ES6 style imports
import {Foo as Bar} from "biz";
//Common JS style requires
var Bar = require("biz");
//AMD style requires
require(["biz"], function (Bar) {
If you want to use your node_modules in a browser, you'll want to bundle them using Browserify, Webpack, Rollup or similar. To automate this, you can easily use Grunt tasks such as grunt-browserify together with grunt-watch.
Same applies for your CSS files: You store your own files under css and if you need CSS files from node_modules you can import them to your own files: if you are using some preprocessor (such as SASS or LESS), the preprocessors usually inline your imports when building the .css-file. If you are just using plain .css files, see grunt-css-import for example.
I've got a preamble.lessimport file with definitions of standard colors, sizes, mixins etc. that I import in all other .less files. So far, the file was placed in /client and I included it with
#import '/client/preamble.lessimport';
Worked as a charm.
Now, I'm moving all styles to a smart package to make them reusable. How do I include the preamble now?
I've tried putting it as preamble.lessimport in the main package dir and then including with both
#import '/preamble.lessimport';
and
#import 'preamble.lessimport';
Both result in the compile error:
While building package `theme`:
input: Less compiler error: '/preamble.lessimport' wasn't found
Placing the file in a subfolder didn't help. The file is added in package.js and I use less package in both client and server.
How can I properly import that file?
Edit:
I've worked around this issue by importing via relative path:
#import '../../../preamble.lessimport';
However I'm not happy with that solution as the package is on early stage and files inside tends to move a lot. Is there any absolute path I could use?
As of meteor 0.7 you no longer use the .lessimport extension. Your less files should have the .import.less extension.
Take a look at how the bootstrap3-less project imports bootstrap for best use examples.