參數預設值，剩餘參數，拓展參數(default spread rest parameter)

預設參數

    let aa=(name='wwrs')=>{
        console.log(`Hello ${name}`);
    }
    aa();//Hello wwrs
    aa('sss');//Hello sss

擴展參數

    let bb=(a,b,c)=>{
        console.log(a+b+c);//9
    }
    let dd=[2,3,4];
    bb(...dd);

剩餘參數

let he=(a,b,c,d)=>{
    console.log(a+b+c+d);//10
}
he(1,2,3,4)

let he1=(s,j,...shi)=>{
    console.log(shi);//[3, 4]
}
he1(1,2,3,4)