class Circle {
    draw() {
        console.log('画一个圆形');
    }
}
class Decorator {
    constructor(circle) {
        this.circle = circle
    }
    draw() {
        this.circle.draw()
        this.setRedBorder(circle)
    }
    setRedBorder(circle) {
        console.log('设置红色边框');
    }
}

// 测试
let circle = new Circle()
circle.draw()
let dec = new Decorator()
dec.draw()

function readonly(target, name, descriptor) {
    descriptor.writable = false
    return decorator
}

class Peson {
    constructor() {
        this.first = 'A'
        this.last = 'B'
    }
    @readonly
    name() {
        return `first:${this.first} last:${this.last}`
    }
}

let p = new Person()
console.log(p.name())
// first:A last:B
p.name = function () {
    alert(100)
}
// 报错

function log(target, name, descriptor) {
    let oldValue = descriptor.value
    descriptor.value = function () {
        console.log(`calling ${name} width`, arguments);
        return oldValue.apply(this, arguments)
    }
    return descriptor

}

class Math {
    @log
    add(a, b) {
        return a + b
    }
}

let math = new Math()
const result = math.add(2, 4)
console.log('result', result);