js class

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 Car {
2  constructor(brand, speed) {
3    this.brand = brand
4    this.speed = speed
5  }
6  speedUp() {
7    this.speed += 5
8    console.log(`The ${this.brand} is travelling at ${this.speed} mph`)
9  }
10  slowDown() {
11    this.speed -= 5
12    console.log(`The ${this.brand} is travelling at ${this.speed} mph`)
13
14  }
15}
16const redCar = new Car('toyota', 0)
17redCar.speedUp() // result: The toyota is travelling at 5 mph
18redCar.slowDown() // result: The toyota is travelling at 0 mph
19

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

1class MyArray extends Array {
2  // Overwrite species to the parent Array constructor
3  static get [Symbol.species]() { return Array; }
4}
5
6let a = new MyArray(1,2,3);
7let mapped = a.map(x => x * x);
8
9console.log(mapped instanceof MyArray); // false
10console.log(mapped instanceof Array);   // true
11

1const Animal = {
2  speak() {
3    console.log(`${this.name} makes a noise.`);
4  }
5};
6
7class Dog {
8  constructor(name) {
9    this.name = name;
10  }
11}
12
13// If you do not do this you will get a TypeError when you invoke speak
14Object.setPrototypeOf(Dog.prototype, Animal);
15
16let d = new Dog('Mitzie');
17d.speak(); // Mitzie makes a noise.
18

1
2class ClassName {
3
4   constructor() { ... }
5
6  method_1() { ... }
7
8  method_2() { ... }
9
10  method_3() { ... }
11
12}
13