I have a feeling the author doesn't understand Promises well. In my opinion, they are in fact designed poorly, but I don't see any problems with points the author describes.
He doesn't like that the callback is called immediately - but Promises just represent a result that will be available later and do not guarantee (and should not) when the function will be called. If you want to delay some function call, do it explicitly or use a delay promise.
In my opinion, the main problem with promises is broken error handling. They don't play well with exceptions. For example:
var p = Promise(function (res, rej) {
throw new RuntimeError("System is broken");
});
This code will just ignore the error. While it is expected that the runtime error would float up and terminate the program - that is what runtime errors are made for.
This also makes writing tests more difficult because tests often use exceptions to indicate failure.
I have some ideas how to fix it (neither is perfect), but the comment will become too long.
He doesn't like that the callback is called immediately - but Promises just represent a result that will be available later and do not guarantee (and should not) when the function will be called. If you want to delay some function call, do it explicitly or use a delay promise.
In my opinion, the main problem with promises is broken error handling. They don't play well with exceptions. For example:
This code will just ignore the error. While it is expected that the runtime error would float up and terminate the program - that is what runtime errors are made for.This also makes writing tests more difficult because tests often use exceptions to indicate failure.
I have some ideas how to fix it (neither is perfect), but the comment will become too long.