Isobit

Haven't tried a custom layout myself (only xkbOptions), but it should be fairly straightforward to use a custom xkb layout with NixOS: https://nixos.wiki/wiki/Keyboard_Layout_Customization

Wouldn't this layer of dust also stop the lense from working normally? If I understand the other commenters here, it's not just about reversibility, but "useful energy" loss - with lenses you are not paying the needed "efficiency tax" to achieve higher temperatures than the source.

Interesting. I did add a return to that benchmark and it didn't seem to affect the results. I would think your test would be identical to mine in performance characteristics, I wonder if it's just the benchmarking methods leading to the difference. I might just go write my own benchmarking like yours since I don't really know what measurethat.net is doing.

It seems intuitively obvious that map would be less efficient, but who knows what V8 is doing to optimize under the hood.

Mind sharing the code you were testing this with? I have actually seen map perform better than for loops in Chrome in some cases (see https://www.measurethat.net/Benchmarks/Show/1096/0/map-vs-fo...).