Going Beyond Google: Are Search Engines Ready for JavaScript Crawling & Indexing?

I recently published the results of my JavaScript SEO experiment where I checked which JavaScript frameworks are properly crawled and indexed by Google. The results were shocking; it turns out Google has a number of problems when crawling and indexing JavaScript-rich websites. Google managed to index only a few out of multiple JavaScript frameworks tested. And as I proved, indexing content doesn't always mean crawling JavaScript-generated links. If Google is having problems with JavaScript crawling and indexing, how are Google's smaller competitors dealing with this problem?