ES6 继承、多态简单demo

继承demo：

class Animal{
constructor(shoutVoice, speed){
this._shoutVoice = shoutVoice;
this._speed = speed;
}

get speed(){
return this._speed;
}

shout(){
console.log(this._shoutVoice);
}

run(){
console.log('本上仙的速度可是有' + this.speed);
}
}

class Dog extends Animal{
constructor(){
super('汪汪汪', '10m/s');
}

gnawBone(){
console.log('这是本狗最幸福的时候');
}

run(){
console.log('本狗的速度可是有' + this._speed);
super.run();
}
}

class PoodleDog extends Dog{
constructor(){
super();
this._breed = 'poodle';
}

get breed(){
return this._breed;
}
}

let poodleDog = new PoodleDog();
console.log(poodleDog.breed);
console.log(poodleDog.speed);
poodleDog.shout();
poodleDog.run()
poodleDog.gnawBone();

console.log:
poodle
10m/s
汪汪汪
本狗的速度可是有10m/s
本上仙的速度可是有10m/s
这是本狗最幸福的时候

多态demo：

class Animal{
eat(food){
console.log('"' + this.constructor.name + '"类没有eat()方法.');
}
}

class Snake extends Animal{}

class Dog extends Animal{
eat(food){
console.log('本狗在啃' + food);
}
}

class Cat extends Animal{
eat(food){
console.log('这只猫在吃' + food);
}
}

let snake = new Snake();
snake.eat('老鼠');

let dog = new Dog();
dog.eat('骨头');

let cat = new Cat();
cat.eat('鱼');

console.log：
"Snake"类没有eat()方法.
本狗在啃骨头
这只猫在吃鱼