Javascript-字节数组要长吗？

Question

I have a byteArray constructed from Java, which contains longs . I need to be able to read these longs in Javascript. I understand that Javascript does not support longs by default. Is there any way around this? Can I read it as a String instead?

Thanks

Answer 1

The DataView.getInt64() implementation below will let you do it with enough precision:

How to Read 64-bit Integer from an ArrayBuffer / DataView in JavaScript

Answer 2

I want to share my trick that may be useful for someone.

My java server sends for all clients positions of players with long timestamp from System.currentTimeMillis() via binary websocket message. On client side to parse this message I am using DataView .

But DataView dont have method getInt64() . And my solution was to send long in two pieces.

On server side:

long time = System.currentTimeMillis();
int firstPiece = (int)(time / 1000);
short secondPiece = (short)(time % 1000);

On client side:

let data = {};
let view = new DataView(binary);
data.t = view.getInt32(offset) * 1000 + view.getInt16(offset + 4);

And that also saves 2 bytes (long 8 bytes > int 4 bytes + short 2 bytes), but it will work until 2038 year https://en.wikipedia.org/wiki/Year_2038_problem .