src/css.js
function createHash(input) {
	let hash = 0;
	if (input.length === 0) {
		return hash;
	}
	for (let i = 0; i < input.length; i++) {
		const char = input.charCodeAt(i);
		hash = ((hash << 5) - hash) + char;
		// Convert to 32bit integer
		hash &= hash;
	}
	return hash;
}
function createHash(input) {
	let hash = 0;
	if (input.length === 0) {
		return hash;
	}
	for (let i = 0; i < input.length; i++) {
		const char = input.charCodeAt(i);
		hash = ((hash << 5) - hash) + char;
		// Convert to 32bit integer
		hash &= hash;
	}
	return hash;
}
Based on http://werxltd.com/wp/2010/05/13/javascript-implementation-of-javas-string-hashcode-method/