import React from 'react' interface Animal { animalStuff: any } interface Dog extends Animal { dogStuff: any } class AnimalHouse { resident: Animal constructor(animal: Animal) { this.resident = animal } } class DogHouse extends AnimalHouse { // Initializes 'resident' to 'undefined' // after the call to 'super()' when // using 'useDefineForClassFields'! // @ts-ignore resident: Dog // useless constructor only for type checker /* eslint-disable @typescript-eslint/no-useless-constructor */ constructor(dog: Dog) { super(dog) } } class DogHouseWithDeclare extends AnimalHouse { declare resident: Dog // useless constructor only for type checker /* eslint-disable @typescript-eslint/no-useless-constructor */ constructor(dog: Dog) { super(dog) } } export default function AnimalView() { const dog = new DogHouse({ animalStuff: 'animal', dogStuff: 'dog', }) const dogDeclare = new DogHouseWithDeclare({ animalStuff: 'animal', dogStuff: 'dog', }) return ( <>