autoprefixer.js

import process from 'node:process';
import childProcess from 'node:child_process';
import getStdin from 'get-stdin';
import postcss from 'postcss';
import autoprefixer from 'autoprefixer';
import postcssSafeParser from 'postcss-safe-parser';
import postcssScssParser from 'postcss-scss';

const subprocess = childProcess.spawn('npx', ['browserslist@latest', '--update-db'], {
	cwd: import.meta.dirname, stdio: 'ignore',
});

subprocess.unref();
subprocess.on('error', () => {});

const data = await getStdin();
const options = JSON.parse(process.argv[2]);

if (options.browsers) {
	options.overrideBrowserslist = options.browsers;
	delete options.browsers;
}

const postcssParser = options.is_css ? postcssSafeParser : postcssScssParser;

try {
	const {css} = await postcss(autoprefixer(options)).process(data, {
		parser: postcssParser,
		from: undefined,
	});

	process.stdout.write(css);

	// TODO: Log warnings in an non-error way somehow.
	// const warnings = result.warnings();

	// if (warnings.length > 0) {
	// 	console.error(warnings.join('\n  '));
	// }
} catch (error) {
	if (error.name === 'CssSyntaxError') {
		error.message += `\n${error.showSourceCode()}`;
	}

	console.error(error.message.replace('<css input>:', ''));
}