Treat sideEffects array as inclusion list

[mikeharder]

• Fixes sideEffects array is treated as exclusion list #226

[lukastaegert]

Why are you including the index? I think it is very instructive to see that in case a side-effect-free file reexports from side-effect-ful file, only the latter file is included.
Otherwise thanks so much for spotting this. It goes to show that testing does not mean everything is working as intended if the test is bananas 🙄

[mikeharder]

If I remove ./index.js from the sideEffects array, then none of the array- files are included:

      AssertionError [ERR_ASSERTION]: Input A expected to strictly deep-equal input B:
+ expected - actual

  [
    'false-dep1',
    'true-dep1',
    'true-dep2',
-   'true-index'
+   'true-index',
+   'array-dep1',
+   'array-dep3',
+   'array-dep5',
+   'array-index'
  ]

Is this by design, or might this be another bug?

[lukastaegert]

See my comments regarding inclusion of index in the test and slightly simplifying the hasModuleSideEffects function

[mikeharder]

@lukastaegert: I believe I have made all the requested changes, with the exception of removing ./index.js from the sideEffects array, since I'm not sure if the resulting behavior is a bug or by design.

[lukastaegert]

You are right, index needs to be included for the other files to be included because that is how side-effects work. Thanks for the fix, looks good to me!