Modify visibility within a subclass

Question

Modify visibility within a subclass

Is there a way to modify property visibility in a child class from protected to public? Consider the following code snippet:

class BaseFoo  {
    protected foo;
}

class Foo extends BaseFoo {
   foo = 1;
}

new Foo().foo;

It seems that this change is possible from protected to public, but not in any other direction. In fact, changing the visibility accidentally to public by omitting the modifier can be more harmful than attempting to change from protected to private (which is not allowed). What could explain this behavior? Is it a known issue?

typescript

Answer 1

Answer №1

After some careful consideration, it appears that the question has already been deliberated upon and subsequently closed as "working as intended" in the repository here. While my knowledge of OOP theory may be limited, I have come to understand the rationale behind the maintainer's perspective regarding the concept of protected methods within a class hierarchy.

class Foo extends BaseFoo {
   protected foo = 1;
}

This snippet illustrates how to maintain the privacy of the property foo within the child class Foo, while still allowing access to it from derived classes. As for the query regarding implicit property types (specifically, whether foo = 1 should default to public), it seems reasonable to expect such behavior. In TypeScript, defaulting to a public modifier is consistent across the language, and if there is a need to restrict this accessibility, one could employ the following approach:

class BaseFoo  {
    private foo;
}

class Foo extends BaseFoo {
   foo = 1; // results in a compiler error
}

Answer 2

After some careful consideration, it appears that the question has already been deliberated upon and subsequently closed as "working as intended" in the repository here. While my knowledge of OOP theory may be limited, I have come to understand the rationale behind the maintainer's perspective regarding the concept of protected methods within a class hierarchy.

class Foo extends BaseFoo {
   protected foo = 1;
}

This snippet illustrates how to maintain the privacy of the property foo within the child class Foo, while still allowing access to it from derived classes. As for the query regarding implicit property types (specifically, whether foo = 1 should default to public), it seems reasonable to expect such behavior. In TypeScript, defaulting to a public modifier is consistent across the language, and if there is a need to restrict this accessibility, one could employ the following approach:

class BaseFoo  {
    private foo;
}

class Foo extends BaseFoo {
   foo = 1; // results in a compiler error
}

Modify visibility within a subclass

Answer №1

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