JavaScript Source Maps Support

[rjanicek]

Maybe it's possible to use source maps for better "view source" and doc reporter when testing with minified JS or languages that compile to JS.

http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/

Thank you.

[lavrton]

+1

[tj]

this shouldn't really have anything to do with Mocha, you can compile source maps for own code if you like

[ashnur]

I might be wrong about this, but what I see is that even though I compile source maps for my code (and I checked that these source maps really work), if an Exception is thrown, mocha reports only the bundle.js file which has the minified/concatenated code.

[lavrton]

Ashnur, you are rigth. Also problem with line numbers.

[tj]

that's not the concern of mocha though, you can compile source maps (or use sourceurl) if you're aggregating

[ashnur]

@visionmedia I am sorry, but I don't understand your response. I mean I understand the meaning of it, but it seems to me, that you just repeated your last response and have not reponded to me. That or I must be completely missing the point somewhere, and I am unaware of not just what it is, but where I am missing it.

I am using mocha in the browser on a code which has to be browserified in order to work there. I use the browserify feature of compiling source maps for the code, and they work properly, as long as I am not trying to use the code with mocha. When I use it with mocha, the source maps go away, I only get the original file and line nr. references, not the source maps, which - I repeat the third time - are there.

So please, if you do not mind taking the time, explain to me what else should I do so that I can use the compiled source maps with mocha?

[tj]

hmm I'm not sure why they would go away when using Mocha, maybe the browsers just don't respect source maps for err.stack, I dont think there's anything we can do about that

[juliangruber]

that's my impression too...

[jacobbubu]

May I use mocha in this way mocha --compilers coffee:"coffee-script --map" to support source map?

[tj]

@jacobbubu nope, if you use coffeescript you're screwed just about everywhere on the server-side for error mapping

[actionshrimp]

If anyone's still interested in source mapped stack traces, @evanw has recently added browser compatability (using browserify) to node-source-map-support here: evanw/node-source-map-support@70c343e

Note that it relies on Error.prepareStackTrace which I believe is only paid attention to by Chrome, so source mapped stack traces only work there, but it's working a treat for me :)

[shanebdavis]

+1

Reading the comments above, I think there is some misunderstanding. My understanding of the original posters request is that Mocha's HTML output after running the tests contains stack traces which do not use source-maps.

I use Coffeescript + source-maps which work pretty well with Chrome's developer tools, but they are ignored by Mocha.

For anyone using Coffeescript or other javascript preprocessors, a stack trace of the generated javascript is not very helpful. My productivity would increase quite a bit if all stack traces Mocha outputs used source-maps, when available.

[tj]

I'm definitely against doing anything custom to pull in source maps, I don't see why the browser can't do this for you when the developer tools are open etc, pretty silly to force every client lib to handle this.

[asheb]

Dirty hack to make it work with PhantomJS. May come in handy.

[krunkosaurus]

+1. I realize from what @visionmedia replied that this necessarily isn't a direct Mocha issue but any more visibility into getting this working would be good. I test prod code with Mocha which means I test compressed code. If I can't see real line numbers in the errors it makes Mocha half as useful as it should be.

[dreampulse]

I solved this problem with node-source-map-support

require('source-map-support').install();

describe('APIs', () => {

    it('should do something', (done) => {

       throw new Error();
       ///....

    });

  });
});

Now the stacktrace is pointing to the "correct" source file.

I hope this will help you :-)

[boneskull]

@dreampulse This is great information. Care to post it in the wiki?

[liukun]

Agree with @dreampulse
Better set the following option in coffeescript when install

    require('source-map-support').install
      handleUncaughtExceptions: false

Otherwise, function handleUncaughtExceptions in module source-map-support will call process.exit(1) and terminate mocha process without ending properly.

[corelgott]

@dreampulse +1

[rosskevin]

FYI - source-map-support also supports chrome - lifesaver for debugging.

https://github.com/evanw/node-source-map-support#browser-support