Typescript: Return "this" from generic base class

Question

I want to return "this" from the base class as the generics type parameter.

class ExampleClass<T> {
    public returnThis = (): T => {
        return <T>this;
    }
}

I know that i cannot cast to T because typescript doesn't know that T derives from ExampleClass.
But is there a way to do this?

Answer 1

You can just return type this:

class ExampleClass<T> {
    public returnThis = (): this => {
        return this;
    }
}

It's covered in the Polymorphic this types section of the docs.

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Edit

No, it will return the type of the actual instance, for example:

class BaseClass {
    public returnThis(): this {
        return this;
    }
}

class ExampleClass extends BaseClass {}

let base = new BaseClass();
let base2 = base.returnThis(); // base2 instanceof BaseClass

let example = new ExampleClass();
let example2 = example.returnThis(); // example2 instanceof ExampleClass 

(code in playground)