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Comment by majke | Hacker News Reader

If I understand correctly you're saying that JavaScript is a neutral language. It's only a coincidence that in Browsers and in Node.js it heavily relies on the callback style. As a language itself, it could be synchronous.

Well, my friend, with this logic I claim that C is purely functional (it's only a coincidence that some implementations use rw memory) and there's nothing stopping Lisp from having mutable data.

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You can claim that there exists a subset of C that can be considered purely functional, and others have argued that (http://conal.net/blog/posts/the-c-language-is-purely-functio...), but the existence of standard library functions like strtok makes the general statement false.

You can claim that nodejs HTTP module forces a callback style, and that is true given the implementation, but javascript spec doesn't force you to implement an HTTP server in that fashion. As I stated in both responses, the article claims that javascript forces you to use a callback style, which is not the case. It is Node that forces you to use callbacks.

> If I understand correctly you're saying that JavaScript is a neutral language. It's only a coincidence that in Browsers and in Node.js it heavily relies on the callback style. As a language itself, it could be synchronous.

I remember that I once wrote a JS library that loaded another page in an iframe and simply polled it to see if it had the data I wanted soon. These days, I probably would have written the server to respond with 202 Accept and then just timeout and poll again in X milliseconds. Block until it was ready, if need be.

It's not hard, and it's not even particularly frowned upon.

There are javascript implementations that don't go asynchronous though. Take rhino for example: http://stackoverflow.com/questions/7249252/read-file-with-rh... . Or check out the commonjs spec: http://wiki.commonjs.org/wiki/Filesystem/A#Files .

Unfortunately such a claim is false. The event loop and callback oriented asynchrony model is baked into the ES spec itself; future ES features rely on it explicitly.

You are probably confusing ES spec with DOM spec, if not, at least I cannot find anything in ES spec even remotely related to how anything built on top would have to be asynchronous.

The concept of an event loop and event loop 'turns' is backed into ES promises the last time I read the draft spec and kept up with the spec discussions. It's not something you can polyfill in older versions of JS, it's a platform feature designed around how browsers work.

Hmm, do you recall where the ES promises spec lives? I can't find it in the ES6 draft ( http://people.mozilla.org/~jorendorff/es6-draft.html ), but it's in the DOM spec ( http://dom.spec.whatwg.org/#promises ). ES6 does end up having iterators, which does look useful for promises, though... see task.js.

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