('%02x'):format(Number) in Node Js - node.js

Question

Trying to convert lua encryption to Node.JS, just need this in it.
("%02x"):format(c)
Once, I got that I'll have it in node.js, so
I tried buffer and it didn't work.
Tried a few other things, and they also didn't work.
Orginal post for this encryption: Low impact encryption formula for ROBLOX Lua
Lua Code:
local Key53 = 8186484168865098
local Key14 = 4887
local inv256
function encode(str)
if not inv256 then
inv256 = {}
for M = 0, 127 do
local inv = -1
repeat
inv = inv + 2
until inv * (2*M + 1) % 256 == 1
inv256[M] = inv
end
end
local K, F = Key53, 16384 + Key14
return (str:gsub('.',
function(m)
local L = K % 274877906944 -- 2^38
local H = (K - L) / 274877906944
local M = H % 128
m = m:byte()
local c = (m * inv256[M] - (H - M) / 128) % 256
K = L * F + H + c + m
--print("lol ".. c)
--print(('%02x'):format(c))
return ('%02x'):format(c)
end
))
end
function decode(str)
local K, F = Key53, 16384 + Key14
return (str:gsub('%x%x',
function(c)
local L = K % 274877906944 -- 2^38
local H = (K - L) / 274877906944
local M = H % 128
c = tonumber(c, 16)
local m = (c + (H - M) / 128) * (2*M + 1) % 256
K = L * F + H + c + m
return string.char(m)
end
))
end

Answer 1

The %02x just convert a decimal to hex. In JS it could be done that way:
function toHex(value) {
let hex = value.toString(16);
if ((hex.length % 2) > 0) {
hex = "0" + hex;
}
return hex;
}
Outputs:
toHex(120) // 78
('%02x'):format(120) -- 78