The basic demo doesn't work.

[szhu]

I'm following the basic demo here:
https://github.com/evanw/node-source-map-support#basic-demo

npm install source-map-support

echo 'throw new Error("test"); // This is the original code' > original.js

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

throw new Error("test"); // This is the compiled code
// The next line defines the sourceMapping.
//# sourceMappingURL=compiled.js.map' > compiled.js

echo '{
  "version": 3,
  "file": "compiled.js",
  "sources": ["original.js"],
  "names": [],
  "mappings": ";;;AAAA,MAAM,IAAI"
}' > compiled.js.map

node compiled.js

And I get:

.../compiled.js:3
throw new Error(test); // This is the compiled code
      ^
Error: test

[szhu]

Oh there's also #97

[jeremytm]

Same here. Is this project still active??

[jeremytm]

After looking around, I see that node removed the call to prepareStackTrace which this module relies on... So the obvious question is: if it doesn't work anymore, why does this module still exist?

[uiteoi]

There is an error in documented compiled.js.map, an extra semi-column at the start of "mappings", try this instead and it will work:

echo '{
  "version": 3,
  "file": "compiled.js",
  "sources": ["original.js"],
  "names": [],
  "mappings": ";;AAAA,MAAM,IAAI"
}' > compiled.js.map

[LinusU]

Fixed in 0.4.15

[uiteoi]

You might also want to close issue #97 which seems to describe the same issue.

[jeremytm]

Thanks team. I've got things working.

Part of the reason I thought this was broken and tried the demo is because I couldn't get it to work in my own project.

The problem turned out to be this line from your README:

Once you have a valid source map, insert the following line at the top of your compiled code:

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

I was inserting this line at the top of an already compiled file (as the instructions said) and then expecting it to work. But my sourcemaps are generated by babel at the same time as compilation, so with an extra line added after the sourcemap had been generated, things got messed up.

The fix ended up being to insert this line in the original file before compilation, and then everything worked.

I'm happy to submit a PR request for the README, but could someone confirm that how I'm doing things is correct?

[uiteoi]

@jeremytm, The error in README/basic demo was an extra semi-column at the start of "mappings". It is now fixed.

For Babel, you indeed need to include require('source-map-support').install(); in the source file otherwise mappings would be wrong. There are examples in README for TypeScript and CoffeeScript which should be similar to what could be done with Babel.

There is also another option for Babel mentioned in README:
"Note: if you're using babel-register, it includes source-map-support already."