onSerialize
Commit a0b2d36415 (diff-3975e0ee5aa3e06ecbcd76f5fa5134612f7fd2e6802ca7d370973bd410aab55cR25-R31) changed the serialization phase logic so that when the state is empty the script tag is not added to the document. As a side effect, this caused the `toJson` not called which caused the `onSerialize` callbacks also not to be called. These callbacks are used to provide the value for a key when `toJson` is called. Example: https://github.com/ngrx/platform/issues/101#issuecomment-351998548 Closes #47172 PR Close #47888
a0b2d36415 (diff-3975e0ee5aa3e06ecbcd76f5fa5134612f7fd2e6802ca7d370973bd410aab55cR25-R31)