TypeScript - Classes - Inheritance and constructors

Now, in my Inherited class I can create its own constructor overriding the constructor in the parent class:

class City {

public name:string;

private type: string;

protected elevation: number;

constructor(name:string) {

this.name = name;

this.type = "city";

this.elevation = 505;

}

setElevation(elevation:number){

this.elevation = elevation;

console.log("new elevation = "+this.elevation);

}

getElevation(){

console.log(this.elevation);

}

setType(type:string){

this.type = type;

console.log("new type = "+this.type);

}

printType(){

console.log(this.type);

}

}

const city = new City("Hyderabad");

console.log(city);

city.getElevation();

city.setElevation(506);

city.printType();

city.setType("Metro");

city.printType();

class Visakhapatnam extends City{

name = "Visakhapatnam";

protected elevation = 45;

constructor(){

super("Visakhapatnam");

}

}

const cityVisakha = new Visakhapatnam();

console.log(cityVisakha);

console.log(cityVisakha.name);

cityVisakha.setType("Town");

console.log(cityVisakha.printType());

console.log(cityVisakha.getElevation());

console.log(cityVisakha);

As you observe, in the constructor of the inherited class - i call the super() function. The super function indicates that I am calling the constructor of the parent class. Since, the constructor of the parent class expects a input. Hence, we pass an input to the super("Visakhapatnam") function.

But, while instantiating the child class - we do not pass in any arguments. This is because, the constructor in the child class does not expect any input arguments.