let a = {aa:'aa'};
let b = {bb:'bb'};
let c = {...a,...b};
console.log(c); // {"aa":"aa","bb":"bb"}
let d = ['dd'];
let e = ['ee'];
let f = [...d,...e];
console.log(f); // ["dd","ee"]
var aa= [1,5,7];
var bb = [2,4];
aa.splice( 1 , 0 , ...bb ); //在数组索引1,后面第0个替换为新的数组,并展开数组内容
console.log(aa); // [1, 2, 4, 5, 7]