index.js

const Benchmark = require('benchmark');
const path = require('path');
const fs = require('fs');
const clsx = require('clsx');
const classnames = require('classnames');

function bench(name, { title, before, after }) {
	console.log(`\n# ${name} - ${title}:`);

	const suite = new Benchmark.Suite();

	suite.add('before - classnames', () => before(classnames));
	suite.add('before -    clsx   ', () => before(clsx));

	// If the argument length is 0 then the function call has been optimized away
	if (after.length === 0) {
		suite.add('after  -    N/A    ', after);
	} else {
		suite.add('after  - classnames', () => after(classnames));
		suite.add('after  -    clsx   ', () => after(clsx));
	}

	suite.on('cycle', (e) => console.log('  ' + e.target));
	suite.run();
}

const dir = path.join(__dirname, 'cases');
fs.readdir(dir, (err, files) => {
	if (err) {
		throw err;
	}

	files.forEach((f) => {
		const testCase = require(path.join(dir, f));

		bench(f, testCase);
	});
	console.log();
});