previousValue for SimpleChange might be undefined #67516
Description
Which @angular/* package(s) are the source of the bug?
core
Is this a regression?
No
Description
The new type of SimpleChange does not reflect the possible undefined value for the public previousValue property.
However, the previousValue might be undefined during runtime, e.g. for the first change.
Please provide a link to a minimal reproduction of the bug
No response
Please provide the exception or error you saw
Please provide the environment you discovered this bug in (run ng version)
Angular 21.x.x
Anything else?
No response