TypeScript计算机编程语言（图文教程）

TypeScript是微软开发的一个开源的编程语言，通过在JavaScript的基础上添加静态类型定义构建而成。TypeScript通过TypeScript编译器或Babel转译为JavaScript代码，可运行在任何浏览器，任何操作系统。
官网地址：https://www.typescriptlang.org/zh/

变量类型

1. 类型推断
2. 类型注解

let numArr = [1, 2, 3]
const result = numArr.find(item => item >2)
result * 5

let v1: string = 'abc'
let v2: number = 10
let v3: boolean = true
let nu: null = null
let un: undefined = undefined

let v4: string|null = null
let v5: 1 | 2 | 3 = 5

let arr: number[] = [1, 2, 3, 'abc']
let arr1:Array<string> = ['a','b',3]

let t1: [number, string,number] = [1,'a']
let t2: [number, string,number?] = [1,'a']

枚举类型

enum MyEnum{
    A,
    B,
    C
}
console.log(MyEnum.A)
console.log(MyEnum[0])

函数定义

function aabb(a=10,b: string, c?:boolean, ...rest: number[] ): number{
    return 100
}

 const f = aabb(1,"2",true, 2,3,4,"a" )

接口

interface Obj{
    name: string,
    age: number
}

const myobj: Obj = {
    name: "a",
    age:"10"
    sex:5

}

类型别名

type MyUserName = string | number
let a: string | number = 'abc'
let b: MyUserName = 'abc'

泛类型

function myFn(a: T, b:T): T[]{
    return [a,b]
}
myFn<number>(1,2);//可以
myFn<number>(1, "a");//不可以，报错