Something like Tristan Hume's famous blog post [0] on Tree Diffing would be unthinkable at Amazon, or most likely even Google or FB. If it's for internal use, they'd just slap together whatever works and looks nice, test the crap out of it and launch (part 2 optional). Nobody would want to spend weeks minimizing the white space like this, especially over 5 weeks.
I know multiple people who have interned at Trading companies - all making more than $9k a month - working on optimizing React rendering for tables. They have solutions that are amazing and wonderful because they are superior engineers and computer scientists than mere mortals like me, but for the problem space it seems pretty ridiculous.
I know people who have done crazy stuff that has gone into production during their Google, Facebook, or even lesser companies like Amazon internships but were compensated a fraction ($6k a month at Amazon vs. $10k a month at JS). I guess this is the dollar value difference of prestige.