AMP-CSS

AMP (Accelerated Mobile Pages) is a project by Google and the Digital News Initiative aiming to improve the speed of websites by utilizing a special JavaScript framework.

This comes with restrictions to the size and contents of CSS. This package provides a binary to compile SCSS files only if the resulting CSS is valid for AMP. Also it provides a way to insert CSS into a (static) HTML page.

Installing

NPM

npm install --save-dev @saithodev/amp-css

PNPM

pnpm install --save-dev @saithodev/amp-css

Yarn

yarn add --dev @saithodev/amp-css

Command overview

Compile SCSS to CSS

The following example will compile the file path/to/my/scss/style.scss into the CSS file path/to/my/css/style.css if there is no invalid CSS inside and the file size does not exceed AMP's size limit.

amp-css process path/to/my/scss/style.scss path/to/my/css/style.css

Alternatively you can also set an output directory. The following line does exactly the same as the line above:

amp-css process --output-dir path/to/my/css path/to/my/scss/style.scss

Inserting CSS into a HTML file

AMP requires websites to embed the stylings using inline CSS. There is a command that will look for the "Custom AMP CSS" area in a HTML file and overwrite its contents with the content of a given CSS file.

amp-css assign -s mycss.css index.html

Using in build scripts

We recommend defining scripts inside your projects package.json:

"scripts": {
    "build": "npm run-script build-css && npm run-script assign-css",
    "build-css": "amp-css process -s assets/scss/styles.scss assets/css/styles.css",
    "assign-css": "amp-css assign -s assets/css/styles.css index.html"
}

In the example above calling npm run-script build (or yarn build) will compile the CSS file and insert it into the index.html file.

Processing multiple files

There currently is no support for compiling multiple SCSS files or inserting multiple CSS files. I currently don't see a use case for that.

If your stylings consists of multiple stylings, @import them all in one SCSS file which you then compile.