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Comment by googletron | Hacker News Reader

what do people use to make sure the JavaScript they write is valid, as they write it. Not something I run on my code after the fact?

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I use Komodo IDE. Both their IDE version and the free Komodo Edit have near-realtime syntax checking for JavaScript, Python, Ruby, Perl, PHP, and one or two other languages. You get red squiggly underlines for syntax errors, green squigglies for warnings. It's quite nice to know that my code is at least free of syntax errors before I even save the file.

I recommend the 7.0 release candidate:

http://downloads.activestate.com/Komodo/releases/

More info:

http://www.activestate.com/komodo-ide http://www.activestate.com/komodo-edit

JS2-mode for Emacs[1][2] does this. It is awesome.

[1]: Original version: http://code.google.com/p/js2-mode/

[2]: Improved (IMO) fork: https://github.com/mooz/js2-mode

Additionally, you can configure JS[HL]int to use flymake[3]. The trick is to improve performance by having it talk to a running JavaScript process (e.g. a node server) instead of starting a new one each time.

[3]: http://www.emacswiki.org/emacs/FlymakeJavaScript#toc3

I code with SublimeText 2, which validates JS files as soon as I save them using a local Node instance of jshint.com and a plugin called SublimeLint. It took a while to set up but the productivity gain is well worth it.

Nice. Quick off-topic question: assuming you have experience with TextMate, do you find SublimeText 2 to be slightly better than TextMate or significantly better?

I general I have heard and seen that SublimeText is better than TextMate and look good as well. The fact that most of the plugins from TextMate work with Sublime means it is a no-brainer which to use.

I use SublimeText on Linux and haven't got any first-hand experience of TextMate. I have seen coworkers use it and as far as I can tell, the main difference between them is SublimeText is much faster. It loads in under 1 second on an old PC and working with files feels instantaneous. It's also available cross platform so you can get the same experience on any computer. Well worth installing the trial then shelling out for the licence IMO.

javascript-tools for TextMate. Calls JSHint on every save and quickly gives you the number of errors. Also allows a full check using JSLint or Closure linter, minifying etc.

https://github.com/subtleGradient/javascript-tools.tmbundle

I'm learning CoffeeScript right now, is what I write using it always valid JavaScript?

The valid CoffeeScript you write is always valid JavaScript :)

Can there be invalid CoffeScript?

of course, why not? any syntax can be broken.

I meant something that would not be detected when compiling to JavaScript from CoffeeScript. Maybe I got it all wrong and CoffeeScript just translates without performing any checks. Also I thought maybe the subset of code you can write with CoffeeScript can't be invalid, if it were wrong it just wouldn't work.

I use jshint as a vim plugin.

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