Function workerize

src/index.js:20–53

(code, options)

 *	})();
 */
export default function workerize(code, options) {
	let exports = {};
	let exportsObjName = `__xpo${Math.random().toString().substring(2)}__`;
	if (typeof code==='function') code = `(${Function.prototype.toString.call(code)})(${exportsObjName})`;
	code = toCjs(code, exportsObjName, exports) + `\n(${Function.prototype.toString.call(setup)})(self,${exportsObjName},{})`;
	let url = URL.createObjectURL(new Blob([code],{ type: 'text/javascript' })),
		worker = new Worker(url, options),
		term = worker.terminate,
		callbacks = {},
		counter = 0,
		i;
	worker.kill = signal => {
		worker.postMessage({ type: 'KILL', signal });
		setTimeout(worker.terminate);
	};
	worker.terminate = () => {
		URL.revokeObjectURL(url);
		term.call(worker);
	};
	worker.call = (method, params) => new Promise( (resolve, reject) => {
		let id = `rpc${++counter}`;
		callbacks[id] = [resolve, reject];
		worker.postMessage({ type: 'RPC', id, method, params });
	});
	worker.rpcMethods = {};
	setup(worker, worker.rpcMethods, callbacks);
	worker.expose = methodName => {
		worker[methodName] = function() {
			return worker.call(methodName, [].slice.call(arguments));
		};
	};
	for (i in exports) if (!(i in worker)) worker.expose(i);
	return worker;
}

function setup(ctx, rpcMethods, callbacks) {
	ctx.addEventListener('message', ({ data }) => {