feat: added support for .css files imported by Js modules

[tubalmartin]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• metadata update

Motivation / Use-Case

In some scenarios, such as the one I encountered at my current company, a JS module may import a .css file and then webpack will process it with say, postcss-loader & css-loader.

If you need to nullify that .css file using this loader, the output of null-loader won't be valid CSS since CSS does not support single line comments // ... and thus, css-loader or postcss-loader will throw an error (SyntaxError) and webpack will stop bundling.

Since both CSS and JS support multi-line or block comments /* ... */ I think it's sensible to use this form instead of single line comments.

Breaking Changes

Additional Info

[jsf-clabot]

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[alexander-akait]

Need test

[codecov]

Codecov Report

Merging #20 into master will not change coverage.
The diff coverage is 50%.

@@           Coverage Diff           @@
##           master      #20   +/-   ##
=======================================
  Coverage   77.77%   77.77%           
=======================================
  Files           2        2           
  Lines           9        9           
  Branches        1        1           
=======================================
  Hits            7        7           
  Misses          2        2

Impacted Files	Coverage Δ
src/index.js	66.66% <50%> (ø)	⬆️

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[tubalmartin]

@evilebottnawi what test?

[alexander-akait]

https://github.com/webpack-contrib/null-loader/blob/master/test/loader.test.js with fixture when it is happens

[alexander-akait]

Close in favor #24