The point was that it's not a single value, it's a stream of values (e.g the compileServer can start working with partial results of the compileBrowser function

The point was that it's not a single value, it's a stream of values (e.g the compileServer can start working with partial results of the compileBrowser function). Of course if it was a single value, promises are fine. A simpler and more modern alternative would be async iterators/generators[0]. [0] https://blog.logrocket.com/comparing-the-stream-api-and-async-generators-in-node-js-v10/ https://blog.logrocket.com/comparing-the-stream-api-and-asyn...