Asynchronous stylesheets loading with HTML Webpack Plugin
Referencing CSS stylesheets with link[rel=stylesheet] or @import causes browsers to delay page rendering while a stylesheet loads. When loading stylesheets that are not critical to the initial rendering of a page, this blocking behavior is undesirable. The new <link rel="preload"> standard enables us to load stylesheets asynchronously, without blocking rendering.
npm install --save-dev async-stylesheet-webpack-plugin
- Latest release: https://github.com/devpreview/async-stylesheet-webpack-plugin/releases
- NPM: https://www.npmjs.com/package/async-stylesheet-webpack-plugin
The plugin will update all your webpack bundles stylesheets in the head using link tags with rel="preload" attribute.
Just add the plugin to your webpack config as follows:
webpack.config.js
const HtmlWebpackPlugin = require('html-webpack-plugin')
const AsyncStylesheetWebpackPlugin = require('async-stylesheet-webpack-plugin');
module.exports = {
...
plugins: [
new HtmlWebpackPlugin(),
new AsyncStylesheetWebpackPlugin(),
...
]
}This will generate a file dist/index.html containing the following:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Webpack App</title>
<link href="app.css" rel="preload" as="style" onload="this.onload=null;this.rel='stylesheet';">
<noscript><link href="app.css" rel="stylesheet"></noscript>
</head>
<body>
<script src="app.js"></script>
</body>
</html>You can pass a hash of configuration options to async-stylesheet-webpack-plugin. Allowed values are as follows:
| Name | Type | Default | Description |
|---|---|---|---|
preloadPolyfill |
{Boolean} |
false |
If true then enabled legacy browser support |
noscriptFallback |
{Boolean} |
true |
If true then enabled fallback stylesheets loading without JavaScript |
Here's an example webpack config illustrating how to use these options:
webpack.config.js
module.exports = {
...
plugins: [
new HtmlWebpackPlugin(),
new AsyncStylesheetWebpackPlugin({
preloadPolyfill: true,
noscriptFallback: true
}),
...
]
}If preloadPolyfill option is enabled (this option disabled by default) async-stylesheet-webpack-plugin adding in HTML head cssrelpreload.js provided by loadCSS.
This will generate a file dist/index.html containing the following:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Webpack App</title>
<script type="text/javascript">/* here is the content of the cssrelpreload.js */</script>
<link href="app.css" rel="preload" as="style" onload="this.onload=null;this.rel='stylesheet';">
<noscript><link href="app.css" rel="stylesheet"></noscript>
</head>
<body>
<script src="app.js"></script>
</body>
</html>If noscriptFallback option is enabled (this option enabled by default) async-stylesheet-webpack-plugin adding in HTML head noscript tag with traditional stylesheet loading.
This will generate a file dist/index.html containing the following:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Webpack App</title>
<link href="app.css" rel="preload" as="style" onload="this.onload=null;this.rel='stylesheet';">
<noscript><link href="app.css" rel="stylesheet"></noscript>
</head>
<body>
<script src="app.js"></script>
</body>
</html>If noscriptFallback option is disabled async-stylesheet-webpack-plugin only updated link tags:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Webpack App</title>
<link href="app.css" rel="preload" as="style" onload="this.onload=null;this.rel='stylesheet';">
</head>
<body>
<script src="app.js"></script>
</body>
</html>- loadCSS - A function for loading CSS asynchronously;
- HTML Webpack Plugin - Simplifies creation of HTML files to serve your webpack bundles.
- all-chunks-loaded-webpack-plugin - Provide callback executed after all chunks loaded;
- Script Extension for HTML Webpack Plugin - Enhances html-webpack-plugin functionality with different deployment options for your scripts including 'async', 'preload', 'prefetch', 'defer', 'module', custom attributes, and inlining;
- preload-webpack-plugin - A webpack plugin for injecting into HtmlWebpackPlugin pages, with async chunk support.
Welcome to issues!
- Bundles filtering.