I'm trying to provide a dynamic return type for an inherited method by passing the child Class to the parent. Please find a small example below. Currently it's not working and I'm thinking I am not far off.
I'm aware that a workaround is to manually declare each inherited method in each child class is an option, and simply calling super() from within but that's not as elegant a solution as I was hoping for.
I'm hoping someone can help me figure out the generic types or if it's at all possible.
Thanks in advance:
/**
* The Animal base class
* @class
*/
class Animal {
/**
* @param {T} classType
*/
constructor (classType) {
this.classType = classType
}
/**
* @returns {T} A baby of the same type as the parent instance
*/
giveBirth () {
return new this.classType()
}
}
/**
* The Dog class
* @class
* @extends Animal
*/
class Dog extends Animal {
constructor () {
super(Dog)
}
bark () {
return 'woof'
}
}
const dog = new Dog()
const babyDog = dog.giveBirth()
babyDog.bark() // JSDoc does not consider it an instance of Dog
Adding @template for Animal and correct extend (@extends Animal<Dog>) works for me
/**
* The Animal base class
* @class
* @template T
*/
class Animal {
/**
* @param {T} classType
*/
constructor (classType) {
this.classType = classType
}
/**
* @returns {T} A baby of the same type as the parent instance
*/
giveBirth () {
return new this.classType()
}
}
/**
* The Dog class
* @class
* @extends Animal<Dog>
*/
class Dog extends Animal {
constructor () {
super(Dog)
}
bark () {
return 'woof'
}
}
const dog = new Dog()
const babyDog = dog.giveBirth()
babyDog.bark()