参数默认值，剩余参数，拓展参数(default spread rest parameter)

参数默认值，剩余参数，拓展参数(default spread rest parameter)

默认参数

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

扩展参数

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

剩余参数

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)