CODEWITHSUNDEEP
typescripttypescript-typings
ziv
ziv

Reputation: 3870

typescript return type of inherited class

This is what I'm trying to do:

class Base{
    clone(){
        //return new instance of the inherited  class 
    }
}

class Derived extends Base{
}

const d1=new Derived();
const d2=d2.clone; // I want d2 to be of type Derived

What should be the the return type of the clone method for d2 to be of type Derived?

Upvotes: 16

Views: 6384

Answers (1)

Aviad Hadad
Aviad Hadad

Reputation: 1717

I really hope there is a better way, but here is what I currently do:

class Base{
    clone(): this {
        return new (this.constructor as any)(); 
    }
}

class Derived extends Base {
}

class DerivedAgain extends Derived {

}

const d1=new Derived();
const d2 = d1.clone(); 
const d3 = new DerivedAgain().clone();

d2 is of type Derived, and d3 is of type DerivedAgain, as expected.

Upvotes: 20

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