Anyone have any suggestions on how to perform arithmetic on 64bit integers in Node.js? The node-int64 package doesn't seem to support that.
Javascript does not support 64 bit integers, because the native number type is a 64-bit double, giving only 53 bits of integer range.
You can create arrays of 32-bit numbers (i.e. Uint32Array) but if there were a 64-bit version of those there'd be no way to copy values from it into standalone variables.
There are some modules around to provide 64bit integer support:
Maybe your problem can be solved using one of those libraries.