[nunull]

Regarding 1: I think the sorting approach is actually really nice in this case. Clearly it's not as efficient as a simple loop, but it's safer and more readable. Explicit looping and mutation can introduce nasty bugs which this kind of declarative approach can't.

[madflame991]

No need to mutate/slice/sort anything

    Math.max(...lines.map((line) => ctx.measureText(line).width))

[ola]

I am of the same opinion, always go for correctness before performance, efficiency can be tuned later if it's even needed.