Base cases that take dependencies upon information potentially supplied by
subclass have to be intentionally design to make that work. And the chosen
design should be document as part of its subclassing contract. For the example
shown there is there is a long known pattern that can be used:
class Base {
constructor() {
....
.. idAttribute ..
....
}
idAttribute = this.__idInitializer(); //initial id value may be
supplied by a subclass
__idInitialier() {
// override this method if you want your subclass to provide an
alternative initial idAttribute value
// the subclass override method should not be dependent upon
subclass fields.
return ‘id’;
’}
}
class Derived extends Base {
constructor() {
super();
....
}
__idInitializer() {return ‘_id’}
}
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