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.

Answer 1

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

Answer 2

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.

Answer 3

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/

Answer 4

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

Answer 5

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.

Answer 6

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
        ]
    }]
}