2.typescript代码练习

 

//元组--需要显式的注解类型，数组

let a:[number] = [1]

let b:[string,string,number] = ["a","b",1]

//b = ["a","a","a"]错误

let trainFares:[number,number?][]=[  //中括号的问号表示可选

    [3.8],

    [8.3,6],

    [10.5]

]

//等价

let moreTrainFares:([number]|[number,number])[]=[[3.8],

[8.3,6],

[10.5]]

let friends:[string,...string[]] =['a','b'];

let aa:[number,...number[]] = [1,2,3]

console.log("元组的值："+aa[1])

//元组类型不同的列表

let list2:[number,boolean,...string[]] = [2,true,'c','d','e']

console.log(list2[0])

console.log(list2[1])

console.log(list2[2]);

console.log(list2[3]);

console.log(list2[4]);

type A = readonly string[]

type B = ReadonlyArray<string>

type C = Readonly<string[]>

type D =readonly[number,string]

type E =Readonly<[number,string]>

function fun_a(x:number)//typescript函数，方法

{

    if(x<10)

    {

        return x

    }

    return null;

}

function func_b()

{

    return undefined

}

function func_c()

{

    let a= 2+2;

    let b = a*a;

}

function func_D()

{

    throw TypeError('al err') //typescript抛出异常

}

function func_e()

{

    // while(true)

    // {

    // }

}

//枚举

enum Language2

{

    achinease,

    english,

    spanish,

    russian

}

enum Language2a

{

    achinease=0,

    english=1,

    spanish=2,

    russian=3

}

let myFirstlan = Language2.achinease

let mySecondlan= Language2["english"]

const enum Flippable{

    Burger = "Gurger",

    Chair ="Chair",

    Cup ="cup",

    Skateboard ="Skateborad",

    Table ="Table"

}

function flip(f:Flippable)

{

    return 'flipped it la'

}

flip(Flippable.Cup)

flip(Flippable.Chair)

//flip(12)

//flip("hat")

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