Chrome DevTools has implemented code-folding (as of v73 apparently)!

Open Chrome devtools settings, then under preferences, sources, enable "code folding", then code suddenly becomes more manageable in DevTools :)

https://developers.google.com/web/updates/2019/01/devtools#folding

https://bugs.chromium.org/p/chromium/issues/detail?id=328431#c33

Before:

After enabling code-folding: