编辑代码

const str: string = 'hello';
const arr: string[] = ['123', '23123']
const obj: any = {name: 'lili',age: '12', sex: '女'}
const obj1: {name: string
    age: string
    sex: string
} = {name: 'lili',age: '12', sex: '女'}
for(const item of arr) {
    console.log(item)
}
for(const item in obj1) {
    console.log(item)
}

function funHandle(name?: string): void {
    const a = 1;
    console.log(a)
}

const Hi = (name: string) => {
    console.log(name)
}

enum Msg{
    Hi = 'hi',
    Hello = 'hello'
}

interface A {
    say(name: string): void;
}

class B implements A {
    say(name: string) {
        console.log(`${name}, I'm B class`)
    }
}
const res:A = new B()
res.say(Msg.Hello)


class Rectagle{
    private width: number;
    private height: number;
    constructor(width: number, height: number) {
        this.width = width
        this.height = height
    }
    public area(): number {
        return this.width * this.height
    }
    public area1(): number {
        return this.width * this.height
    }
}

class Squre extends Rectagle {
    constructor(side: number) {
        super(side, side)
    }
}

const size = new Squre(10)
console.log(`the size is ${size.area()}`)