Debugging CoffeeScript line-by-line

Question

Is there a way to debug CoffeeScript line-by-line?

I understand that it compiles into Javascript. But this sounds like it could make it a pain to debug.

Since the generated JavaScript preserves indentation, names of functions and variables debugging it's not nearly as bad as most people think. Also, support for "Source Maps" is coming (in the next version?) in CoffeeScript to address this: http://www.coffeescriptlove.com/2012/04/source-maps-for-coffeescript.html — Hector Correa, Jun 19 '12 at 14:13
You can configure [coffeescript debbuging in JetBrains WebStorm](http://www.youtube.com/watch?feature=player_detailpage&v=Sl1Uk3zT5Fg) — Maxim Yefremov, Apr 02 '13 at 16:09

score 36 · Answer 1 · answered Oct 23 '12 at 11:10

36

Update: there's currently a redesign of coffeescript compiler that generates source maps, which should enable you to debug your coffeescript in most recent versions of Google Chrome (18 and upwards I think).

I think it's not production-ready yet, but it's worth mentioning.

answered Oct 23 '12 at 11:10

Miguel Ping

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Pay attention that source maps are available only for Chrome Canary, WebKit nightly and Firefox 23+. BTW, that's will be the best way to debug compiled javascript code at client-side, so +1 for ur answer ;) – Wilk Jul 02 '13 at 13:22
Available in Chromium 39, current version in Ubuntu Trusty repositories. And, well, "non-production-readiness" doesn't restrict its usage during development. – D-side Feb 04 '15 at 10:09

score 29 · Answer 2 · answered Jul 17 '12 at 11:50

29

if you are running coffeescript from the terminal you can debug it line-for-line using node-inspector, launching your script this way:

coffee --nodejs --debug-brk yourscript.coffee

answered Jul 17 '12 at 11:50

Lloyd

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for debugger auto connection I'm using `coffee --nodejs debug yourscript.coffee` – dmi3y Apr 24 '15 at 17:40

score 14 · Accepted Answer · answered Jun 17 '12 at 00:33

14

At the moment it is quite a pain to debug CoffeeScript. Most people use lots of unit tests.

There is some work being done on debugging for CoffeeScript but it is probably a while away before we'll have a really good debugger. One example is http://www.infoq.com/news/2011/08/debug-languages-on-javascript-vm

answered Jun 17 '12 at 00:33

leonm

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Creepy unit tests to avoid happy call-stack debugging?? Yikes! – Esteban Jun 17 '12 at 18:38
I'll drop bugger here: https://github.com/jkrems/bugger. It has step-by-step debugging for coffee-script 2.x. For coffee-script 1.x there's the strongloop-fork of node-inspector: https://github.com/strongloop/node-inspector – Jan Olaf Krems Jul 22 '13 at 11:51

srus · Answer 4 · 2014-07-14T10:49:32.617

9

Yes, with node-inspector:

npm install -g node-inspector

By putting the statement debugger into the source code of your script, you will enable a breakpoint. Then type in a console:

coffee -c -m myscript.coffee
node-debug myscript.js

Node Inspector supports source-maps out of the box, so no extra configuration is needed.

For more information see this post.

edited Jul 14 '14 at 10:49

answered Jul 14 '14 at 09:53

srus

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It's fascinating but how do I make him take my `require 'something.coffee'` into account? – Loic Coenen Jul 02 '16 at 11:31

lhk · Answer 5 · 2018-11-18T11:46:34.700

5

Coffeescript now supports source maps: http://coffeescript.org/

Jetbrains for example supports this feature: https://blog.jetbrains.com/ruby/2013/01/whats-mining-coffeescript-debugger/

edited Nov 18 '18 at 11:46

answered Mar 12 '13 at 18:51

lhk

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There is Jetbrains: http://blog.jetbrains.com/ruby/2013/01/whats-mining-coffeescript-debugger/ – dan-klasson Mar 13 '13 at 03:34

defend orca · Answer 6 · 2020-11-19T20:17:44.480

now is 2020, i find this question, and then i find vscode support sourcemap, so we can use vscode to debug coffee directly.

btw, i think coffee need a great improve. just like static data. anyway here is my launch.json:

{
    "version": "0.2.0",
    "configurations": [{
        "type": "node",
        "request": "launch",
        "name": "Launch Program",
        "skipFiles": [
            "<node_internals>/**"
        ],
        "program": "${file}", //important, make sure debug current file
        "outFiles": [
            "${workspaceFolder}/dist/api/api.js" //important, where to find sourcemap js file
        ]
    }]
}

Debugging CoffeeScript line-by-line

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