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

Similar questions

Version 4 of Typescript is experiencing crashes when spreading optional arguments

Warning from React 17: Unexpected presence of <a> tag inside <div> tag in server-rendered HTML

Troubleshooting the "TypeError: Swiper.initialize is not a function" Issue in React Swiper using TypeScript

Tips on modifying the selected type key name through Pick?

Error message displayed indicating script not found after executing yarn tsc within a Docker container

Guide on implementing conditional return types in React Query

waiting for the import statement in a React/NextJS/Typescript project to resolve

Tips for creating a unit test case for a specialized validator in angular reactive forms

Typescript encountering difficulty in accessing an array saved in sessionStorage

There was an error linking the module "electron_common_features" which caused the Electron react test to fail

Utilizing interpolation for a CSS class defined in an external file within Angular 2

Converting md ElementRef to HtmlElement in Angular 2+: A Step-by-Step Guide

Tips for preventing error TS2345 when importing TypeScript components from outside the project directory in Vue

An issue arises following an upgrade in Angular from version 9 to version 10, where the property 'propertyName' is being utilized before it has been initialized

Working with Typescript to map and sort the key values of a new datasource object

Simulating service calls in Jest Tests for StencilJs

Is it possible to pass additional arguments to setState other than prevState and props?

Unable to utilize the forEach() function on an array-like object

Definition of a Typescript Global.d.ts module for a function that is nested within another function

What is the solution for addressing the deprecation warning "The 'importsNotUsedAsValues' flag will no longer work in TypeScript 5.5"?