how to write classes in JS code example

Example 1: javascript create class

class Person {
 constructor(name, age) {
   this.name = name;
   this.age = age;
 }
  present = () => { //or present(){
  	console.log(`Hi! i'm ${this.name} and i'm ${this.age} years old`) 
  }
}
let me = new Person("tsuy", 15);
me.present();
// -> Hi! i'm tsuy and i'm 15 years old.

Example 2: javascript class

// Improved formatting of Spotted Tailed Quoll's answer
class Person {
	constructor(name, age) {
		this.name = name;
		this.age = age;
	}
	introduction() {
		return `My name is ${name} and I am ${age} years old!`;
	}
}

let john = new Person("John Smith", 18);
console.log(john.introduction());

Example 3: javascript classes

let Person = class {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
}