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What is the equivalent of protected in TypeScript?
I need to add some member variables in the base class to be used only in derived classes.
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protected implies that the method or property is accessible only internally within the class or any class that extends it but not externally. Finally, readonly will cause the TypeScript compiler to throw an error if the value of the property is changed after its initial assignment in the class constructor.
TypeScript supports three access modifiers - public, private, and protected.
Protected. A Protected access modifier can be accessed only within the class and its subclass. We cannot access it from the outside of a class in which it is containing.
TypeScript provides three access modifiers to class properties and methods: private , protected , and public . The private modifier allows access within the same class. The protected modifier allows access within the same class and subclasses. The public modifier allows access from any location.
November 12th, 2014. Version 1.3 of TypeScript is available and includes the protected keyword.
September 26th, 2014. The protected keyword has landed. It is currently pre-release. If you are using a very new version of TypeScript you can now use the protected keyword... the answer below is for older versions of TypeScript. Enjoy.
View the release notes for the protected keyword
class A { protected x: string = 'a'; } class B extends A { method() { return this.x; } } TypeScript has only private - not protected and this only means private during compile-time checking.
If you want to access super.property it has to be public.
class A { // Setting this to private will cause class B to have a compile error public x: string = 'a'; } class B extends A { method() { return super.x; } } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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