typescript1.ts

abstract class Building {
   constructor(public stories: number, public size: number) {
   }
   
   public height(): number {
       return this.stories * this.size;
   }
}

class Hardhat extends Building {
    constructor(public address: string) {
        super(1, 3.5);
    }
    
    public details(): string {
        return `I am ${this.address} and I am ${height} meters tall!`;
    }
}

let hhd = new Hardhat("111 High Street");
console.log(hhd);