Creates a WebWorker using the given url.

@param {string} url The url of the worker.

@returns {Worker} The worker.
function createWorker( url ) {
	let worker = null;
	try {
		worker = new Worker( url );
	} catch ( e ) {
		try {
			const blobUrl = createBlobURL( url );
			worker = new Worker( blobUrl );
		} catch ( e2 ) {
			throw e2;
		}
	}
	return worker;
}