續上篇，今天在 firefox 官網看到幾個過去沒用過，但有點興趣的內容
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects

Debugger

執行時一旦碰到 debugger 這個 statement ，就會啟動debugger。

聽起來很像廢話，但小白如我，只有用過在瀏覽器中找到resource裡面的 JS，雙擊標示breakpoint的這個用法。

這邊用個小程式在不同環境試試看效果，但還是Chrome最深得我心 XD

• Safari
  

• Chrome
  

• VSCode
  

Class

Class 是 ES6 才推出的，讓 JS 可以像 C++、Java 一樣，做物件導向的程式設計
OOP 常見的 keyword，如：super, extends, static, private等等也和其他語言相同
這邊就自己寫個小東西玩玩看

class Vehicle {
    
    constructor(type, year) {
        this.type = type;
        this.year = year;
    }

    showInfo() {};
    olderThan(anotherVehicle) {
        return this.year < anotherVehicle.year;
    }
}

class Car extends Vehicle {
    
    constructor(year, licenseNumber) {
        super("car", year);
        this.licenseNumber = licenseNumber;
    }

    showInfo() {
        console.log(`This is a ${this.type} of ${this.year} with license number ${this.licenseNumber}.`)
    }
};

class Bicycle extends Vehicle {
    constructor(year, color) {
        super("bicycle", year);
        this.color = color;
    }

    showInfo() {
        console.log(`This is a ${this.type} of ${this.year} with ${this.color} color.`)
    }
}

var car = new Car("2020", "ABC-0123");
car.showInfo();

var bicycle = new Bicycle("2023", "light green");
bicycle.showInfo();

console.log(`Is car older than bicycle? ${car.olderThan(bicycle)}.`)