useEffect(() => {
  const subscription = api.subscribe();
  return () => {
    // Always cleanup subscriptions!
    subscription.unsubscribe();
  };
}, []);

function isString(value: unknown): value is string {
  return typeof value === 'string';
}

// Usage
if (isString(value)) {
  // value is typed as string here
  console.log(value.toUpperCase());
}

import { pipeline } from 'stream/promises';

await pipeline(
  readableStream,
  transformStream,
  writableStream
);

// No need to handle cleanup manually!