Source maps: <script type="text/coffeescript"> support?

[ashtuchkin]

Am I missing it or there's no support for source maps when compiling coffee in browser?

[vendethiel]

Do browsers even support that?

[kelp404]

👍

[ashtuchkin]

@Nami-Doc That's a good question. The current v3 specification allows it by using a data uri as sourceMappingUrl and additional parameter "sourcesContent". I'm not sure about the browser support though.

[ashtuchkin]

Just checked - it works in Chrome 25.

[kelp404]

include coffee-script.js
https://github.com/jashkenas/coffee-script/blob/master/extras/coffee-script.js

<script type="text/javascript" src="https://raw.github.com/jashkenas/coffee-script/master/extras/coffee-script.js"></script>
<script type="text/coffeescript">
    console.log 'coffee'
</script>

[ghost]

A little off-topic, but I've wondered this for a while... what actual use case is there for <script type="text/coffeescript">? Why not precompile your code beforehand? Wouldn't that be faster in the long run?

[vendethiel]

in the long run?

indeed. I suppose it may be useful for testing purposes ;).

[ashtuchkin]

@kelp404 Yes, I'm aware of how to use it, thank you. The question is about supporting source maps right in the browser.
@mintplant I use it for development & testing of my product extensively. The benefit is that you can do frontend-only development with a basic static files server (I mock server requests anyway).

[kelp404]

@ashtuchkin Sorry, I got a mistake.

[hden]

@ashtuchkin How did you checked comparability? Canary seems to ignore the sourcesContent option.

[ashtuchkin]

I created manually the source map, encoded original text to js string, created property sourcesContent in the source map, then base64-encoded source map and added as a sourceMapUrl to the .js file. Then viewed it in Chrome Dev Tools. Chrome 25 for Linux.

[hden]

Got it working in Canary, too. I think this is possible if we could...

• port JSON.stringify() since it's not supported in IE6
• port a permissive base64 encoder that supports utf-8, because...
  • utf-8 strings are expected in source codes
  • and btoa() is not supported in IE

I'm afraid both of them adds significant LOC to existing code base.

In other hand, If we compile to js with horrible inline source mapping, none of these limits will apply, any thought?
See what's been done by browserify for detail.

[ashtuchkin]

Source mapping is only supported in latest Chromes & Firefox, why should we support it in IE6?

Sent from my iPhone

On 12.03.2013, at 20:38, Hao-kang Den [email protected] wrote:

Got it working in Canary, too. I think this is possible if we could...

port JSON.stringify() since it's not supported in IE6
port a permissive base64 encoder that supports utf-8, because...
utf-8 strings are expected in source codes
and btoa() is not supported in IE
I'm afraid both of them adds significant LOC to existing code base.

In other hand, If we compile to js with horrible inline source mapping like what's been done by browserify, none of these limits will apply, any thought?

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[hden]

Because extras/coffee-script.js need to run in all the browser that is currently supported.
Or do you suggest a user agent string or a global object check to exclude source mapping in whatever browser that does not support it?

[ashtuchkin]

I would suggest first making it optional (needs to be enabled in config hash), and then check for availability of both JSON and btoa. Imho we need not rely on user agent.

This is a small feature and I agree that we should minimize impact on both cycles and file size.

Sent from my iPhone

On 13.03.2013, at 20:27, Hao-kang Den [email protected] wrote:

Because extras/coffee-script.js need to run in all the browser that is currently supported.
Or do you suggest a user agent string or a global object check to exclude source mapping in whatever browser that does not support it?

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[mehcode]

Just a thought. Perhaps http://yepnopejs.com/ to load https://github.com/davidchambers/Base64.js and https://github.com/douglascrockford/JSON-js.

[hden]

It seems that encoded data aren't interpreted in eval'd codest

I wan wrong see the reply from @ashtuchkin below

[ashtuchkin]

I've managed to make it work by adding sourceURL statement in addition to sourceMappingURL. Please, see https://github.com/ashtuchkin/coffee-browser-sourcemaps

[hden]

Awsome! @ashtuchkin Are you going to make a PR? I've have a working branch based on your idea.

[jashkenas]

@hden. Want to finalize and submit your branch as a PR, if it's working?

[ashtuchkin]

@hden no, feel free to submit your PR, I'll be happy to review it if needed.

[jashkenas]

It's on master now, thanks to @hden.

[braco]

I'm not clear on this pull, is this supposed to just work with

<script type="text/coffeescript" src="...">

?