[z3t4]

This article made me angry then I first read it, and now it makes my blood boil. First off there where no colors in JavaScript pre ES6, there where only functions. You can call them first class functions, but those are still functions. A callback is just a function! Then we have side effects, but executing the side effect while returning a promise like in ES6 you are still executing the side effect, even if yo do not call .then() so nothing really changes.

So first you think there is a problem, but there are not any, but by solving the imagined problem you do actually create it. You now have generator functions and "async" (with the async keyword) functions that always returns a promise, and normal functions.

[saagarjha]

I think you didn’t really understand the argument. The author is not saying that the language lacks first-class functions, in fact he requires it for his real point, which is that async and sync functions are not really compatible.

[z3t4]

Prior to ES6 JavaScript did not have async functions, just normal functions. Async functions came from the runtime, not JavaScript the language. For example there is no setTimeout function in JavaScript, it has to be implemented by the framework that runs the JavaScript. Talking about an function being async makes it confusing though. It's better to think of them as events. You call a function that executes a job, and specify a function to be called (an event handler) when the job has been completed. Putting the callback function in the function arguments is just a convention, other conventions are foo.on("ready") = handlerFunction; foo.ready = handlerFunction; foo.error = errorHandler; bar(handlerFunction); biz(successHandler, errorHandler); The callback convention is less verbose and probably why it's the most popular. Using just functions makes you more powerful...