（十）给数组变量添加类型

let nums = [1, 2, 3]

let nums: number[] = [1, 2, 3]

let nums: Array<number> = [1, 2, 3]

interface Product {
    title: string,
    price: number
}

let products: Product[] = [
    {
        title: '纯棉秋裤',
        price: 200
    },
    {
        titlle: '纯棉秋衣',
        price: 199
    }
]