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)