编辑代码

// let age:number = 50
// let height:number = 175.5
// let isStudent:boolean = true
// let isOpen:boolean = false
// let name: string = "Alice"
// let greeting: string = 'Hello, TypeScript!';
// let score:number|null = null
// let description:string|undefined = undefined
// const symbol1 =  Symbol("key1")
// const symbol2 =  Symbol("key2")
// let value:any = 2
// value = "111"
// value = true
// function test(message: string): void {

// }

// function throwError(message: string): never {
//     throw Error(message)
// }

// let person = {
//     name : "John",
//     age : 30,
//     greet() {
//         console.log("Hello, I'm" this.name);
//     }
// }


let a:number[] = [1,2,3];
let b:Array<number> = [2,3,5];

let c:[number,string] = [5,"11"];

enum Color{
    Red = 2,
    Green,
    Blue
}
let color:Color = Color.Red;
console.log(color)

let aunknown:unknown = 5;

function aa():void {
    console.info("aa")
}
aa()

let undefinedvar:undefined = undefined;
let nullvar:null = null;

let unionvar: number|string = 5;

console.log("aunknown===unionvar:"+(aunknown===unionvar));

function test2(num:number, num2?:number) {
    if(num2) {
        console.log("num2:"+num2);
    }else{
        console.log("num:"+num);
    }
}
test2(1,2);
test2(5);

function test3(...arr:number[]) {
    for(let num of arr) {
        console.log(num)
    }
}

test3(1,55,6);
test3(25);