Ever needed to convert integers to bytes and back in javascript?

int2bytes.coffee

INT_BYTES = 8  # but note that javascript only does 2^53


int2bytes = (x) ->
    if x > Number.MAX_SAFE_INTEGER
        throw new Error "Number is larger than Number.MAX_SAFE_INTEGER (2⁵³-1)!"
    bytes = []
    i = INT_BYTES
    loop
        bytes[--i] = x & 0xff
        x = (x - bytes[i]) / 0x100
        break if not i
    bytes

bytes2int = (bytes) ->
    x = 0
    for byte, i in bytes
        x += byte
        if i < bytes.length - 1
            x = x * 0x100
    x