（五）给对象添加类型和使用 type 关键字定义可复用的对象类型

let product: {
    title: string
    price: number
    insTock: boolean
} = {
    title: '纯棉 T 恤',
    price: 99.8,
    inStock: true
}

let product: {
    title: string
    price: number
    insTock: boolean
} = {
    title: '纯棉 T 恤',
    price: 99.8,
    inStock: true
}

// 新，这两个是重复的，但是还是要重新赋值，不利于代码复用
let productLable: {
    title: string
    price: number
    insTock: boolean
} = {
    title: '纯棉秋裤',
    price: 89.8,
    inStock: true
}

type Product = {
    title: string
    price: number
    insTock: boolean
}

// 使用
let product: Product = {
    title: '纯棉 T 恤',
    price: 99.8,
    inStock: true
}

let productLable: Product = {
    title: '纯棉秋裤',
    price: 89.8,
    inStock: true
}