how to use class in js code example

Example 1: js class

class Car {
  constructor(brand, speed) {
    this.brand = brand
    this.speed = speed
  }
  speedUp() {
    this.speed += 5
    console.log(`The ${this.brand} is travelling at ${this.speed} mph`)
  }
  slowDown() {
    this.speed -= 5
    console.log(`The ${this.brand} is travelling at ${this.speed} mph`)

  }
}
const redCar = new Car('toyota', 0)
redCar.speedUp() // result: The toyota is travelling at 5 mph
redCar.slowDown() // result: The toyota is travelling at 0 mph

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());