Heh, any I write that are longer than a dozen characters or a bit hairy I explode like that. Because I know I'll need to understand them in 6 months' time.
Then add white space etc. to them yourself. Build a test suite with enough data extracted from the wild that you're confident that you're not breaking the regex, if it's complicated enough.
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*insert rant about shoddy coders here*
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I'd be shocked if there wasn't something like that already: give it a V8 regexp, and it'll spit it out nicely formatted in /x format.
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