（九）定义嵌套的对象类型

interface product {
    title: string
    price: number
    categroy: {
        name: string

    }
}

interface product {
    title: string
    price: number
    categroy: Categroy
}

interface Categroy {
    name: string
}

let product = {
    title: '纯棉秋裤',
    price: 200,
    categroy: {
        name: '裤子'
    }
}