How generate minified file with source map?

[stasbamiza]

Bug report or feature request?
Bug

ES5 or ES6+ input?
ES5

Uglify version (uglifyjs -V)
[email protected]

Hi!

I use this command for generate minified file with source map:
uglifyjs main.js -o main.min.js --source-map base="F:\UArush\web\angular2-test\test\test"
In main.min.js.map source variable have "..\\main.js" value but need have main.js and in main.min.js didn't add //# sourceMappingURL=/main.min.js.map

Thanks!

[kzc]

didn't add //# sourceMappingURL=/main.min.js.map

Yeah, that's a bug in [email protected].

$ cat main.js
function hello() {
    var hello = "Hello";
    var world = "world";
    console.log(hello + " " + world + "!");
}
hello();

$ uglifyjs -V
3.0.3

$ uglifyjs main.js -c -m --source-map -o main.min.js

$ cat main.min.js.map && echo
{"version":3,"sources":["main.js"],"names":["hello","console","log"],"mappings":"AAAA,QAASA,SAGLC,QAAQC,IAAIF,gBAEhBA"}

$ cat main.min.js && echo
function hello(){console.log("Hello world!")}hello();

It works in [email protected] (which has different command line options):

$ uglifyjs -V
uglify-js 2.7.5

$ uglifyjs main.js -c -m --source-map main.min.js.map -o main.min.js

$ cat main.min.js.map && echo
{"version":3,"sources":["main.js"],"names":["hello","world","console","log"],"mappings":"AAAA,QAASA,SACL,GAAIA,GAAQ,QACRC,EAAQ,OACZC,SAAQC,IAAIH,EAAQ,IAAMC,EAAQ,KAEtCD","file":"main.min.js"}

$ cat main.min.js && echo
function hello(){var l="Hello",o="world";console.log(l+" "+o+"!")}hello();
//# sourceMappingURL=main.min.js.map

[alexlamsl]

sourceMappingURL aren't added by default in 3.x due to one of the feature requests not to - some users are putting them within HTTP response headers instead.

So the command line for that would be:

$ uglifyjs main.js -cmo main.min.js --source-map url=main.min.js.map

[kzc]

@alexlamsl That's not very intuitive using url for the map filename. Can it be documented?

[kzc]

@alexlamsl The more I think about it, it's still a 3.x bug:

This [email protected] command produces both main.min.js and main.min.js.map:

$ uglifyjs main.js -c -m --source-map -o main.min.js

Yet it does not add the source map comment to the end of main.min.js - so it's useless. If uglify is smart enough to know to generate the map filename it can be used in the source map comment.

[mes-studio]

@alexlamsl Maybe you save CLI options from 2.x version for more compatibility

[alexlamsl]

@kzc because if someone needs to serve main.min.js.map but wishes to use X-SourceMap instead, they don't want //# sourceMappingURL= within main.min.js

I think the relevant issue is #1036

[kzc]

@alexlamsl It's your call. But it could be better documented in any case.

[alexlamsl]

@kzc I haven't made up my mind yet - just making sure we are on the same page about X-SourceMap

The rationale behind restructuring the whole sourceMap is to enable previously impossible use cases, mainly caused by all the path-related magic back then, but hardcoding output of sourceMappingURL was also one of those.

There is also options.sourceMap.filename which also defaults to undefined at the moment, which is responsible for the file attribute within .js.map output, which I guess might also caught some people off guard.

While there is no way to even guess a source map file name within minify() because we don't know any output file paths, bin/uglifyjs does have information about that and in theory we can short-circuit --source-map url, i.e. options.sourceMap.url=true to signal CLI to substitute its output .js.map into the URL. We can do the same for --source-map filename.

[kzc]

just making sure we are on the same page about X-SourceMap

Okay, I did not know the backstory about the source map configuration travails. A few lines of documentation with examples for typical usage scenarios is probably sufficient.