Support [jstype = JS_NUMBER] for int64

[pzeinlinger]

protobuf-ts has an option to use Number to represent int64 fields which is often very convenient where int32 2^32 size is not enough to represent a value, but Javascript's MAX_SAFE_INTEGER (2^53) certainly is.

In my case, this happens when dealing with accounting and money.

[smaye81]

Hi, @pzeinlinger. Sorry for the delay. It was actually a conscious decision to not allow this. I see your point, but it's obviously only effective if you can guarantee that no number in that field will ever exceed JavaScript's MAX_SAFE_INTEGER. This may be the case in your scenario, but it could lead to others encountering subtle bugs. Can you provide more detail on why an int64 doesn't meet your needs?

[smaye81]

@pzeinlinger going to close this issue as this is something we don't plan to support. If you have any other issues or comments, feel free to reopen.

[shartte]

This is somewhat disappointing since I was hoping to use this for a field that is used for "millis since epoch" in our schemas.
Having to roundtrip these values via BigInt is a performance concern.
And yes, millis since epoch is number safe given Date#getTime has that particular return type for the same domain.