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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