Style Loader
Adds CSS to the DOM by injecting a <style> tag
Install
npm install style-loader --save-dev
Usage
Simple API
require("style-loader!raw-loader!./file.css");
// => add rules in file.css to documentIt's recommended to combine it with the css-loader: require("style-loader!css-loader!./file.css").
It's also possible to add a URL instead of a CSS string:
require("style-loader/url!file-loader!./file.css");
// => add a <link rel="stylesheet"> to file.css to documentLocal scope CSS
(experimental)
When using local scope CSS the module exports the generated identifiers:
var style = require("style-loader!css-loader!./file.css");
style.placeholder1 === "z849f98ca812bc0d099a43e0f90184"Reference-counted API
var style = require("style-loader/useable!css-loader!./file.css");
style.use(); // = style.ref();
style.unuse(); // = style.unref();Styles are not added on require, but instead on call to use/ref. Styles are removed from page if unuse/unref is called exactly as often as use/ref.
Note: Behavior is undefined when unuse/unref is called more often than use/ref. Don't do that.
Options
insertAt
By default, the style-loader appends <style> elements to the end of the style target, which is the <head> tag of the page unless specified by insertInto. This will cause CSS created by the loader to take priority over CSS already present in the target. To insert style elements at the beginning of the target, set this query parameter to 'top', e.g. require('../style.css?insertAt=top').
insertInto
By default, the style-loader inserts the <style> elements into the <head> tag of the page. If you want the tags to be inserted somewhere else, e.g. into a ShadowRoot, you can specify a CSS selector for that element here, e.g. require('../style.css?insertInto=#host::shadow>#root').
singleton
If defined, the style-loader will re-use a single <style> element, instead of adding/removing individual elements for each required module. Note: this option is on by default in IE9, which has strict limitations on the number of style tags allowed on a page. You can enable or disable it with the singleton query parameter (?singleton or ?-singleton).
convertToAbsoluteUrls
If convertToAbsoluteUrls and sourceMaps are both enabled, relative urls will be converted to absolute urls right before the css is injected into the page. This resolves an issue where relative resources fail to load when source maps are enabled. You can enable it with the convertToAbsoluteUrls query parameter (?convertToAbsoluteUrls).
attrs
If defined, style-loader will attach given attributes with their values on <style> / <link> element.
Usage:
require('style-loader?{attrs:{id: "style-tag-id"}}!style.css');
// will create style tag <style id="style-tag-id">Usage in url mode:
require('style-loader/url?{attrs:{prop: "value"}}!file-loader!style.css')
// will create link tag <link rel="stylesheet" type="text/css" href="[path]/style.css" prop="value">Recommended configuration
By convention the reference-counted API should be bound to .useable.css and the simple API to .css (similar to other file types, i.e. .useable.less and .less).
So the recommended configuration for webpack is:
{
module: {
rules: [
{
test: /\.css$/,
use: [
{ loader: "style-loader" },
{ loader: "css-loader" },
],
},
{
test: /\.useable\.css$/,
use: [
{
loader: "style-loader/useable"
},
{ loader: "css-loader" },
],
},
],
},
}Note about source maps support and assets referenced with url: when style loader is used with ?sourceMap option, the CSS modules will be generated as Blobs, so relative paths don't work (they would be relative to chrome:blob or chrome:devtools). In order for assets to maintain correct paths setting output.publicPath property of webpack configuration must be set, so that absolute paths are generated. Alternatively you can enable the convertToAbsoluteUrls option mentioned above.
Contributing
Don't hesitate to create a pull request. Every contribution is appreciated. In development you can start the tests by calling npm test.
Maintainers
Tobias Koppers |
Kees Kluskens |
LICENSE
MIT
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