Roadmap

    6 - Exercise V

    End of Lesson

    Exercise: Inheritance and Function Return Types

    Objective:

    • Understand how to use inheritance in TypeScript.
    • Define and use function return types.

    Instructions:

    1. Create a TypeScript File:

      • Create a file named exercise5.ts in your src directory.
      • Open exercise5.ts in your text editor and complete the following code:
    ts
    // exercise5.ts
    // Define a class named 'Person' with properties: name (string) and age (number)
    class Person {
      constructor(public name: ??, public ??: number) {}
      // Define a method that returns a greeting message:
      // "Hello, my name is (name) and I am (age) years old."
      greet(): ??? {
        return ???;
      }
    }
    // Define a class named 'Employee' that inherits from 'Person' and adds a new property: jobTitle (string)
    class ?? extends ?? {
      constructor(name: ??, ??: number, public jobTitle: ??) {
        super(??, ??);
      }
      // Override the greet method to include the job title in the message:
      // "Hello, my name is (name), I am (age) years old and I work as a (jobTitle)."
      greet(): ??? {
        return ???;
      }
    }
    // Create a Person object with name: "John", age: 40
    let person = ??;
    // Create an Employee object with name: "Jane", age: 30, jobTitle: "Software Engineer"
    let employee = ??;
    // Log the result of calling the greet method on both objects
    console.log(person.greet());
    console.log(employee.greet());

    Check Solution

    • Compile and run your code
    bash
    npx tsc
    node ./dist/exercise5.js

    Your output in the console should be:

    bash
    > node ./dist/exercise5.js
    Hello, my name is John and I am 40 years old.
    Hello, my name is Jane, I am 30 years old and I work as a Software Engineer.
    Solution: 
    ts
    // exercise5.ts
     
    // Define a class named 'Person' with properties: name (string) and age (number)
    class Person {
      constructor(public name: string, public age: number) {}
     
      // Define a method that returns a greeting message: "Hello, my name is (name) and I am (age) years old."
      greet(): string {
        return `Hello, my name is ${this.name} and I am ${this.age} years old.`;
      }
    }
     
    // Define a class named 'Employee' that inherits from 'Person' and adds a new property: jobTitle (string)
    class Employee extends Person {
      constructor(name: string, age: number, public jobTitle: string) {
        super(name, age);
      }
     
      // Override the greet method to include the job title in the message:
      // "Hello, my name is (name), I am (age) years old and I work as a (jobTitle)."
      greet(): string {
        return `Hello, my name is ${this.name}, I am ${this.age} years old and I work as a ${this.jobTitle}.`;
      }
    }
     
    // Create a Person object with name: "John", age: 40
    let person = new Person("John", 40);
     
    // Create an Employee object with name: "Jane", age: 30, jobTitle: "Software Engineer"
    let employee = new Employee("Jane", 30, "Software Engineer");
     
    // Log the result of calling the greet method on both objects
    console.log(person.greet());
    console.log(employee.greet());