declaration-merging.ts

abstract class Callable {
    call() {
        console.log("Call!")
    }
}
abstract class Activable {
    active: boolean = false
    activate() {
        this.active = true
        console.log("Activating…")
    }
    deactive() {
        this.active = false
        console.log("Deactivating…")
    }
}
class MyClass {
    constructor() {
    }
}
interface MyClass extends Callable, Activable {}