TypeScript入门

环境配置

tsc --init # 生成ts配置文件
tsc --watch

tsconfig.json

解构

数组解构

const arr = [1,2,3]
let [first, second] = arr
console.log(first, second) // 1, 2

const arr = [1,2,3,4,5,6]
let [first,second, ...three] = arr
console.log(first, second, three) // 1, 2, [3,4,5,6]

const arr = [1,2,3,4,5,6]
let [,,,four,,six] = arr
console.log(four, six) // 4, 6

对象解构

const person = { username: '张三', gender: '男' }
let { username, gender } = person
console.log(username, gender) // 张三, 男

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类型别名Type

字符串类型

type Methos = 'get'|'post'

函数类型

type Sum = (n1:number, n2:number) => number

对象类型

type Response = {
	code:number
	msg:string
}

---

Pick

pick 从指定对象上提取一组属性，形成一个新的类型

🌰1.

const obj = {username:'张三', age: 18, gender: '男'}
type obj1 = Pick<obj, 'username'|'age'> // { username: '张三', age: 18 }

🌰2.

import { Provide } from '@midwayjs/decorator'

import { CartModel } from '@/entity'

// 购物车提交数据
type Carts = Pick<CartModel, 'book_id' | 'bookname' | 'bookpic' | 'bookprice' | 'buy_count'>

@Provide()
export class CartService {
  /**
   * 添加商品到购物车
   */
  async addGoodsToCarts(carts: Carts) {
    const cartModel = new CartModel({ ...carts })
    return await cartModel.save()
  }
}

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