Inline critical-path css and load the existing stylesheets asynchronously.
Existing link tags will also be wrapped in <noscript>
so the users with javascript disabled will see the site rendered normally.
This module is installed via npm:
$ npm install inline-critical
const inline = require('inline-critical');
const html = fs.readFileSync('test/fixtures/index.html', 'utf8');
const critical = fs.readFileSync('test/fixtures/critical.css', 'utf8');
const inlined = inline(html, critical);
const inline = require('inline-critical');
const html = fs.readFileSync('test/fixtures/index.html', 'utf8');
const critical = fs.readFileSync('test/fixtures/critical.css', 'utf8');
const inlined = inline(html, critical, {
ignore: [/bootstrap/],
});
inline-critical works well with standard input. You can either pass in the html
cat index.html | inline-critical critical.css
or just flip things around
cat critical.css | inline-critical index.html
or pass in the file as an option
inline-critical critical.css index.html
without having to worry about the correct order
inline-critical index.html critical.css
Run inline-critical --help
to see the list of options.
html
is the HTML you want to use to inline your critical styles, or any other stylesstyles
are the styles you're looking to inlineoptions
is an optional configuration objectstrategy
select the preload strategyextract
will remove the inlined styles from any stylesheets referenced in the HTMLbasePath
will be used when extracting styles to find the files references byhref
attributesignore
ignore matching stylesheets when inlining.selector
defines the element used by loadCSS as a reference for inlining.noscript
specifies position of noscript fallback ('body' - end of body, 'head' - end of head, false - no noscript)replaceStylesheets
takes an array of stylesheet hrefs to replace the original links in the document. (Used by critical when you extract uncritical css to a target file)
The mechanism to use for lazy-loading stylesheets.
[JS] indicates that a strategy requires JavaScript (falls back to <noscript>
).
- default: Move stylesheet links to the end of the document and insert preload meta tags in their place.
- "body": Move all external stylesheet links to the end of the document.
- "media": Load stylesheets asynchronously by adding
media="print"
and swap tomedia="all"
once loaded (https://www.filamentgroup.com/lab/load-css-simpler/). [JS] - "swap": Convert stylesheet links to preloads that swap to
rel="stylesheet"
once loaded. [JS] - "polyfill": Inject LoadCSS and use it to load stylesheets. [JS]
Adopted from critters
MIT