Value display error

[eighteen-k-gold-malow]

node: v12.16.1
os: window x64

var ByteBuffer = require("bytebuffer");

var buf = new ByteBuffer([]);
var num = 3135456464646545920
buf.writeVarint64(num)
var result = buf.flip()
console.log(num.toString())
console.log(result.readVarint64().toString())

output

3135456464646546000
3135456464646545920

[bnoordhuis]

You should file your bug report against the bytebuffer package, not here.

[Hakerh400]

Duplicate of nodejs/help#2268 and nodejs/help#2230.

JavaScript stores all numbers as double-precision binary IEEE 754 floating point values. Each number is internally stored on 64 bits: 1 bit for sign, 52 for mantissa and 11 for exponent. Given that it has limited number of bits available, it can therefore represent only a limited number of different values. Integers are just a small subset of that.

The maximal integer you can safely represent (without losing the precision) is Number.MAX_SAFE_INTEGER, whose value is 9007199254740991. You are trying to represent 3135456464646545920, which is larger than max safe integer, so you lost precision. That is expected.

To solve the problem, you can use BigInt (simply add n to the end of your number). However, I'm not sure how well it works with bytebuffer module.