Postcss-node NPM

postcss-node

Package which allows import of css files under the node.js eg require('styles.css') This package should be used together with postcss-es-modules

Overview

By using require.extensions this package register the handlers which on the fly, on runtime, for each .css file require is transpiling the css content by using postcss. To be able to load the .css file as javascript module, you should use postcss-es-modules post css plugin.

Installation

npm i postcss-node postcss-es-modules

Usage

Firstly we need to provide the proper postcss configuration, you can add it to your package.json, or keep it in separate file eg:

/* postcss.config.js */
module.exports = {
    "plugins": {
        // this plugin will transform css into the js module
        "postcss-es-modules": {
            "inject": {
                // we will use the common js modules
                "moduleType": "cjs"
            }
        }
    }
}

Usage on the cli

You can register the .css/.sass files handle just by the -r node.js option.

node -r postcss-node/register test.js

/* test.js */
const { styles, css } = require('./test.css');
console.log(css);
console.log(styles.a);

/* test.css */
.a {
    color: blue;
}

Usage within the code

Or you can register the handle manually within the code.

node test.js

/* test.js */
const { register } = require('postcss-node');
register();
const { styles, css } = require('./test.css');
console.log(css);
console.log(styles.a);

/* test.css */
.a {
    color: blue;
}

Custom files extensions

The register function is able to take the optional parameter, which will be the array of the file extensions which should be handled by that package. By default, register is attaching handlers for the '.css', '.scss', '.sass', '.less', '.stylus'.

node test.js

/* test.js */
const { register } = require('postcss-node');
register(['.acss', '.bcss', '.css']);
const { styles, css } = require('./test.acss');
console.log(css);
console.log(styles.a);

/* test.acss */
.a {
    color: blue;
}

You can also provide the custom extensions by the POSTCSS_NODE_EXT environment variable like: cross-env POSTCSS_NODE_EXT=.acss,.bcss,.css

Other options

The register function is able to take the two more optional parameter

timeout (POSTCSS_NODE_TIMEOUT) - the timeout of css processing, default 60000 ms
bufferSize (POSTCSS_NODE_BUFFER_SIZE) - the size of buffer used to transfer compiled code from the worker, in case of RangeError [ERR_BUFFER_OUT_OF_BOUNDS]: "length" is outside of buffer bounds error please increase this parameter, default 1024 kB