Luau - Janky readable number rounding implementation

readablenumber.lua

local function readableNumber(number: number, decimalCount: number?): string
	local threshold = 1e-9
	local remainder = math.abs(number)%1
	if math.abs(1 - remainder) < threshold then
		return tostring(math.round(number))
	end

	if not decimalCount then
		decimalCount = 2
	end

	local decimals = 0
	repeat
		decimals += 1
	until decimals >= decimalCount or (remainder * 10^decimals)%1 < threshold
	return string.format("%s%d.%d",
		math.sign(number) < 0 and "-" or "",
		math.abs(math.round(if number >= 0 then math.floor(number) else math.ceil(number))),
		math.round(remainder*10^decimals)
	)
end

This is a (very janky and convoluted) function I wrote up fairly quickly to turn a number into a more readable string but only up to a certain number of digits. I have not benchmarked it, but I expect it's very slow relative to other forms of number to string conversion. I did this mainly just to figure out how difficult it would be, and to provide a basic starting point.

You should prefer string.format("%2.f", number) but if you really need to shave off those extra zeros, this may save a little time (and a need to work with strings directly which is likely still less performant)