The GetMainData function cannot retrieve the changed items.

[daye-liu]

The GetMainData function pushes the changed fields, but if the pushed variable is of type int, for example, a push indicating that the speed has changed to 0, it can cause issues. This is because in Go, the default value of an int variable in a struct is 0. So, is this 0 the result after the change or the default value indicating no change?

[zze0s]

Hi. With Go v1.24 they added a new struct tag for json, omitzero, which should be useful for this scenario, I think 🤔

[daye-liu]

OmitZero only omits fields with no values when converting a struct to JSON, but it is not useful when converting JSON back to a struct. The zero value of the struct's field cannot be distinguished from a missing value. In this case, each field of the struct should be changed to a pointer type, so that unchanged fields are nil instead of zero values.

[zze0s]

This PR does change the values to pointers and some other things. It might need some more work and testing before it's ready.