Class method which returns an array of itself. How to annotate and inherit?
Specify this[] as the return type of your method:
class PageElement { getAll(): this[] {}}class InputElement extends PageElement { aSpecificInputElementMethod() {}}const inputElement = new InputElement();const inputElements = inputElement.getAll();inputElements[0].aSpecificInputElementMethod(); // valid;See it in action on TS Playground.
Not actually an ideal way, but you can specify the return type as the type argument
getAll<T>(): T[]And then call like
getAll<InputElement>The downsides are:
- You need to specify type argument every time you call
getAll - Type argument should always be a valid type
- You can pass any type of an argument
So basically there is not a lot of type safety because it’s up to you to keep the type argument valid every time you call getAll.This will probably cause issues if you are working in a team.
Maybe someone can suggest a way on how to restrict generic type to be an instance of this particular type.