1.展開一個數組 ``` var arr = [1,2,3]; console.log(...arr); //1 2 3 ``` 2.連接數組 ``` var arr4 = [1,2,3]; var arr5 = [4,5,6] console.log([...arr4,...arr5]); //?[1, 2, 3, 4, 5, 6] ``` 3.合并對象 ``` let ajaxData = {name:'xiaoming',age: 18}; let person = {...ajaxData, name: 'jack', adress:'earth' } console.log(person) //{name: 'jack', age: 18, adress: 'earth'} ``` 4.淺復制一個對象 ``` let ajaxData = {name:'xiaoming',age: 18}; let reactPropsAPI = {...ajaxData}; console.log(...ajaxData) // 報錯： 展開運算符不能展開對象 let {name, age} = reactPropsAPI; ```