fix(isDataURI): Fix MIME Types with underscores not getting matched

[pano9000]

Fix isDataURI returning false for perfectly valid strings, more info can be found here: #2121

I've added an additional test case with a MIME type that has an underscore in its name and added the _ (underscore) to the RegExp to match for these cases.

This fixes #2121

(on a side note here: I feel like isDataURI could or maybe even should be rewritten to internally use isMimeType and isBase64 -> that way you would get rid of some code duplication - but that is a completely different topic than this quick bug fix).

Checklist

• PR contains only changes related; no stray files, etc.
• [ ] README updated (where applicable)
• Tests written (where applicable)

[codecov]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (c06fb15) compared to base (531dc7f).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff            @@
##            master     #2122   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          104       104           
  Lines         2308      2308           
  Branches       578       578           
=========================================
  Hits          2308      2308           

Impacted Files	Coverage Δ
src/lib/isDataURI.js	100.00% <100.00%> (ø)

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[WikiRik]

(on a side note here: I feel like isDataURI could or maybe even should be rewritten to internally use isMimeType and isBase64 -> that way you would get rid of some code duplication - but that is a completely different topic than this quick bug fix).

I was just about to suggest this. I think it would be useful to use isMimeType in this PR. Should not be a difficult fix but makes fixing future bugs a lot easier. isBase64 is a nice benefit but I do not expect that to change anytime soon

[pano9000]

wouldn't this be more of a "feat" or "refactor" type of PR then, and out of scope of this bugfix PR?

I can take a shot at this, but I would like to have this bugfix in first, if that makes sense?

[WikiRik]

That indeed makes sense, but I'm not so sure if you want to wait that long. Merging PRs does not happen that often in this library (e.g. look at the last release of over a year ago), so it might be better to combine PRs of the same scope. In this case I would maybe even think about closing this PR and fixing this issue in #2120. That way it also makes more sense to use isMimeType for isDataURI in there since you only have to update a single RegExp

[braaar]

I guess I'm a stickler for keeping PRs minimal and discrete, so I would intuitively be skeptical of @WikiRik's approach. It's a shame that it feels necessary, though.

[profnandaa]

LGTM, thank!