Something that's gotten old years ago is having to constantly look up character codes for various string and byte parsing needs. In a pinch, it's useful for scripting, and V8 optimizes for
str[i] === "ch" specially, but that doesn't help when dealing with binary data like raw UTF-8 buffers. One could save
"a".charCodeAt(0) to a variable, but sufficiently complicated parsing algorithms could be saving dozens of those, and so it'd get unwieldy fast. (As a concrete data point, parsing JSON, a relatively simple language, requires specific awareness of 29 code points:
b, space, newline, carriage return, and horizontal tab.)
I don't have any specific concrete ideas - first idea was
0sa, but those obviously look a bit strange and the second doesn't look delimited enough. But this would make for a very good quality of life improvement around text parsing in JS.