1class ClassMates{
2	constructor(name,age){
3    	this.name=name;
4      	this.age=age;
5    }
6  	displayInfo(){
7    	return this.name + "is " + this.age + " years old!";
8    }
9}
10
11let classmate = new ClassMates("Mike Will",15);
12classmate.displayInfo();  // result: Mike Will is 15 years old!

1class Person {
2 constructor(name, age) {
3   this.name = name;
4   this.age = age;
5 }
6  present = () => { //or present(){
7  	console.log(`Hi! i'm ${this.name} and i'm ${this.age} years old`) 
8  }
9}
10let me = new Person("tsuy", 15);
11me.present();
12// -> Hi! i'm tsuy and i'm 15 years old.

1// Improved formatting of Spotted Tailed Quoll's answer
2class Person {
3	constructor(name, age) {
4		this.name = name;
5		this.age = age;
6	}
7	introduction() {
8		return `My name is ${name} and I am ${age} years old!`;
9	}
10}
11
12let john = new Person("John Smith", 18);
13console.log(john.introduction());

1class Rectangle {
2  constructor(height, width) {
3    this.height = height;
4    this.width = width;
5  }
6  // Getter
7  get area() {
8    return this.calcArea();
9  }
10  // Method
11  calcArea() {
12    return this.height * this.width;
13  }
14}
15
16const square = new Rectangle(10, 10);
17
18console.log(square.area); // 100

1function Animal (name) {
2  this.name = name;
3}
4
5Animal.prototype.speak = function () {
6  console.log(`${this.name} makes a noise.`);
7}
8
9class Dog extends Animal {
10  speak() {
11    console.log(`${this.name} barks.`);
12  }
13}
14
15let d = new Dog('Mitzie');
16d.speak(); // Mitzie barks.
17
18// For similar methods, the child's method takes precedence over parent's method
19