Add sourcemap option to postCSS-loader options

[LinusBorg]

No description provided.

[Tirke]

This is the correct syntax I think.
Maybe change the var in const ?

The warning from postcss-loader is still there. Setting cssSourceMap to true in dev config did the trick but I don't think we want to set this one to true by default ...

I looked around a little bit and this warning is common for people using vue-loader.
See the comment from Evan at the bottom of this thread.

There's no need to use postcss-loader with vue-loader. Just use vue-loader' own postcss option.

But maybe it was added to process css files outside of *.vue files ?

[LinusBorg]

Hm, thanks for testing it out - vuejs/vue-loader#937 might also be of interest, but:

1. Evan's comment doesn't really apply because the current code applies postcss-loader only to the loaders for style files (*.css etc.), not the loaders for <style> blocks in .vue files.

2. While the fix in Dont add postcss loader gratuitously vuejs/vue-loader#937 seems valid to me, it only applies to scenarios where people use <style lang="postcss"> without having explicitly specified a loader for that lang with vue-loader. In our template, we do explicitly define a loader for postcss blocks, and it doesn't include poscss-loader.

Seems some digging will be necessary to make this work. A job for the weekend.

[LinusBorg]

@Tirke I found the issue - it was another mistake in the original PR, a strict false comparison even though options.usePostCSS is undefinedwhen creating the loaders for vue-loader.

That resulted in postss-loader being included where it shouldn't.

The fix I just pushed should solve this.

[Tirke]

You may have forgotten to use constinstead of var for the postcssLoader variable.
Otherwise all good for me, no more warnings, working as expected.

[LinusBorg]

Good eye, but that's cosmetics. Will add this later.