Source map problems

[milankinen]

Continuing from #123 (comment)

@sassanh wrote:
I don't know if it's related to this issue, I don't know if it's specific to my setup too. When I use livereactload with -d it ruins the sourcemaps a little bit, there are 2 problems:

1. files with same name override each other: if I have two files with name reducer.js and if an error occurs in first file, if I click on the location chrome shows in the error traceback (reducer.js:40 for example) it may go to the other reducer.js. It doesn't change in a single load of page, but after each reload it's random.
2. Lines are slightly changed, for example it shows the error happened in line reducer.js:40 but it really happened in line 36 for example. It's always a few lines but sometime I need to re compile code without livereactload to be able to debug.

Another thing that seems weird and may be related is that my bundle is around 7.5MB without livereactload but with livereactload the size reduces to around 6MB.

I just thought maybe these are also related to this thread. Let me know if I should create another issues for these and if I should provide additional information :)

Hmmm, okay... I know there have been some problems with source maps from the very beginning (#2 and #106) but I have no idea how to fix them. Any help/suggestions are warmly welcomed!

[sergiu-paraschiv]

Found out that [ babelify --sourceMapsAbsolute ] solves problem number (1) listed above.
Line numbers are still off.

[sassanh]

@sergiu-paraschiv Great finding. I guess with --sourceMapsAbsolute I don't need recompiling code without livereactload in case of complex bugs, because the line reported is usually close to the line that error occurred in. It should ease the process a lot.

[sergiu-paraschiv]

The first thing I found was that with livereactreload enabled babelify generates a separate sourceMapUrl for each module instead of a big one at the end of the bundle.
Debugging this a bit I found that the source maps are not relative to my app folder.
Quick fix is --sourceMapsAbsolute but I think there's something bigger I'm missing here and the only direction I can go with debugging from here is watchify's incremental builds.
Is livereactreload somehow messing with babelify so that it can't process all the code at once but instead does it a module at a time?

[EugeneZ]

I submitted PR #138 to resolve this. It's mostly working but there are two unresolved issues I could use some feedback on if anyone's interested. Details in the PR.

[sassanh]

@EugeneZ does it solve the line number problem too? or just duplicate filenames?

[EugeneZ]

@sassanh Both! And also adds accurate sourcemaps when changed modules are loaded.

[sassanh]

@EugeneZ great, it seems to be working for me.

[milankinen]

Fixed in version 3.1.1 🎉 🎉

Big applauses to @EugeneZ!