nodejs write 64bit unsigned integer to buffer

Question

I want to store a 64bit (8 byte) big integer to a nodejs buffer object in big endian format.

The problem about this task is that nodejs buffer only supports writing 32bi

Answer 1

Reading / Writing 64bit values:

const int64 = Date.now()   // 1456909977176 (00 00 01 53 36 9a 06 58)
const b = new Buffer(8)
const MAX_UINT32 = 0xFFFFFFFF

// write
const big = ~~(int64 / MAX_UINT32)
const low = (int64 % MAX_UINT32) - big

b.writeUInt32BE(big, 0)  // 00 00 01 53 00 00 00 00
b.writeUInt32BE(low, 4)  // 00 00 01 53 36 9a 06 58

// read
var time = parseInt(b.toString('hex'), 16)
time == int64 // true

I use this code without any special modules.

UPDATE

Works only for numbers <= Number.MAX_SAFE_INTEGER