CLI: `sourcesContent` field in `.map` file should always contain source code

[mems]

Actually we've got :

1. sourceMap: enable source map, create additional .map contains map between generated file and the original source file
2. inlineMap (previously inline): enable source map, inline source map in generated file with original source file content

We need a third option to activate separately source file content inlining (+ add clarity):

1. sourceMap: enable source map, create additional .map file contains source map data
2. inlineSourceMap: enable source map, inline source map data in the generated file
3. inlineSourceMapSource: inline in source map data the source file content (add sourcesContent field)

Related #4223

[danielbayley]

Maybe it should instead match Babel's sourceMap option ([ true, false, 'inline', 'both' ])?

[GeoffreyBooth]

There are lots of downstream tools that rely on the source map options that exist today, so we shouldn’t change the existing API if we don’t need to. But that doesn’t mean we can’t add a new option.

[GeoffreyBooth]

I think I misread this before. So currently, specifying both options will produce both source maps:

coffee --compile --output test.js --map --inline-map --no-header --bare test.coffee

results in both test.js:

console.log('woohoo!');

//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoidGVzdC5qcyIsInNvdXJjZVJvb3QiOiIiLCJzb3VyY2VzIjpbInRlc3QuY29mZmVlIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQUFBLE9BQU8sQ0FBQyxHQUFSLENBQVksU0FBWiIsInNvdXJjZXNDb250ZW50IjpbImNvbnNvbGUubG9nICd3b29ob28hJ1xuIl19
//# sourceURL=~/Sites/coffeescript/test.coffee
//# sourceMappingURL=test.js.map

and test.js.map.

{
  "version": 3,
  "file": "test.js",
  "sourceRoot": "",
  "sources": [
    "test.coffee"
  ],
  "names": [],
  "mappings": "AAAA,OAAO,CAAC,GAAR,CAAY,SAAZ",
  "sourcesContent": [
    "console.log 'woohoo!'\n"
  ]
}

So the ask isn’t that there be an option to generate both, since that’s already possible. That was my initial misreading.

Looking at it again, it sounds like what you’re asking for is that the sourcesContent field in the inline source map is filled in with the CoffeeScript code content. But as of 841b3cd, that’s already happening, as you can see above; and that commit was 7 months before this issue was posted. So what’s the problem with the current output? The fact that enabling both options leaves two comments at the bottom?

[mems]

As I can read in sourcemap.litcoffee, sourcesContent field is only added in source map file, if you add the option inlineMap:

v3.sourcesContent = [code] if options.inlineMap

That means, if you need the source map file, but not the inlined source map in the generated JS file (//# sourceMappingURL=data:application/json;base64,... //# sourceURL=... comments) you can't.
You need an external tool to remove the source mapping comment (extra bytes) to left only the part //# sourceMappingURL=test.js.map

[GeoffreyBooth]

It seems like the fact that sourcesContent is empty in .map files, unless inline maps are also generated, is a bug. sourcesContent should always have the source, whichever option you choose. That’s Babel’s behavior:

 ✦ ./node_modules/babel-cli/bin/babel.js --presets env --source-maps \
--out-file test.babel.js test.js
 ✦ node -e "console.log(JSON.stringify(JSON.parse(require('fs').readFileSync(
'./test.babel.js.map', 'utf-8')), null, 2))"
{
  "version": 3,
  "sources": [
    "test.js"
  ],
  "names": [],
  "mappings": ";;AAAA;;;;;;AACA,QAAQ,GAAR,CAAY,eAAK,GAAjB",
  "file": "test.babel.js",
  "sourcesContent": [
    "import path from \"path\"\nconsole.log(path.sep)\n"
  ]
}

Would having sourcesContent always populated, regardless of source map option, solve your issue?

See also #4671.

[mems]

Yes, that is the right behavior